Correct Java 26.2 Iris world lifecycle

adapters/bukkit/nms/v26_2_R1/src/main/java/art/arcane/iris/core/nms/v26_2_R1/NMSBinding.java

@@ -14,6 +14,7 @@ import art.arcane.iris.core.nms.container.BiomeColor;
 import art.arcane.iris.core.nms.container.Pair;
 import art.arcane.iris.core.nms.container.BlockProperty;
 import art.arcane.iris.core.nms.datapack.DataVersion;
+import art.arcane.iris.core.lifecycle.WorldReplacementSeed;
 import art.arcane.iris.engine.data.cache.AtomicCache;
 import art.arcane.iris.engine.data.chunk.TerrainChunk;
 import art.arcane.iris.engine.framework.Engine;
@@ -53,6 +54,8 @@ import art.arcane.volmlib.util.nbt.tag.CompoundTag;
 import art.arcane.iris.util.common.scheduling.J;
 import it.unimi.dsi.fastutil.objects.Object2IntMap;
 import it.unimi.dsi.fastutil.shorts.ShortList;
+import io.papermc.paper.world.saveddata.PaperLevelOverrides;
+import io.papermc.paper.world.saveddata.PaperWorldMetadata;
 import net.bytebuddy.ByteBuddy;
 import net.bytebuddy.agent.builder.AgentBuilder;
 import net.bytebuddy.agent.builder.ResettableClassFileTransformer;
@@ -116,6 +119,8 @@ import net.minecraft.world.level.levelgen.structure.StructureCheck;
 import net.minecraft.world.level.levelgen.structure.BoundingBox;
 import net.minecraft.world.level.levelgen.structure.Structure;
 import net.minecraft.world.level.levelgen.structure.structures.JigsawStructure;
+import net.minecraft.world.level.storage.PrimaryLevelData;
+import net.minecraft.world.level.storage.SavedDataStorage;
 import net.minecraft.world.level.levelgen.feature.AbstractHugeMushroomFeature;
 import net.minecraft.world.level.levelgen.feature.ConfiguredFeature;
 import net.minecraft.world.level.levelgen.feature.FallenTreeFeature;
@@ -151,10 +156,14 @@ import org.jetbrains.annotations.NotNull;
 
 import java.awt.Color;
 import java.io.File;
+import java.io.IOException;
 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
+import java.nio.file.Files;
+import java.nio.file.LinkOption;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Iterator;
@@ -163,11 +172,18 @@ import java.util.Map;
 import java.util.Optional;
 import java.util.List;
 import java.util.Set;
+import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Executor;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 
 public class NMSBinding implements INMSBinding {
+    private static final long CURRENT_WORLD_DATA_SNAPSHOT_TIMEOUT_SECONDS = 30L;
+
     private final KMap<Biome, Object> baseBiomeCache = new KMap<>();
     private volatile DataVersion dataVersion;
     private final BlockData AIR = Material.AIR.createBlockData();
@@ -1593,6 +1609,105 @@ public class NMSBinding implements INMSBinding {
         }
     }
 
+    @Override
+    public void writeCurrentPaperWorldData(
+            Path sourceWorldDirectory,
+            Path targetWorldDirectory,
+            long seed
+    ) throws IOException {
+        CraftServer craftServer = (CraftServer) Bukkit.getServer();
+        MinecraftServer server = craftServer.getHandle().getServer();
+        PaperLevelOverrides levelOverrides = captureCurrentPaperLevelOverrides(craftServer, server);
+
+        Path targetWorld = targetWorldDirectory.toAbsolutePath().normalize();
+        UUID metadataUuid = UUID.randomUUID();
+        WorldReplacementSeed.copyWithAuthoritativeSeed(sourceWorldDirectory, targetWorld, seed);
+        try (SavedDataStorage savedDataStorage = new SavedDataStorage(
+                targetWorld.resolve("data"),
+                server.getFixerUpper(),
+                server.registryAccess()
+        )) {
+            savedDataStorage.set(PaperWorldMetadata.TYPE, new PaperWorldMetadata(metadataUuid));
+            savedDataStorage.set(
+                    PaperLevelOverrides.TYPE,
+                    levelOverrides
+            );
+        }
+
+        List<Path> requiredDataFiles = List.of(
+                targetWorld.resolve("data/minecraft/world_gen_settings.dat"),
+                targetWorld.resolve("data/paper/metadata.dat"),
+                targetWorld.resolve("data/paper/level_overrides.dat")
+        );
+        for (Path requiredDataFile : requiredDataFiles) {
+            if (!Files.isRegularFile(requiredDataFile, LinkOption.NOFOLLOW_LINKS)) {
+                throw new IOException("Current Paper world data was not written: " + requiredDataFile);
+            }
+        }
+
+        long writtenSeed = WorldReplacementSeed.readAuthoritativeSeed(targetWorld);
+        if (writtenSeed != seed) {
+            throw new IOException("Current Paper world data did not retain the requested seed.");
+        }
+
+        try (SavedDataStorage verificationStorage = new SavedDataStorage(
+                targetWorld.resolve("data"),
+                server.getFixerUpper(),
+                server.registryAccess()
+        )) {
+            PaperWorldMetadata metadata = verificationStorage.get(PaperWorldMetadata.TYPE);
+            if (metadata == null || !metadataUuid.equals(metadata.uuid())) {
+                throw new IOException("Current Paper world metadata could not be verified.");
+            }
+            PaperLevelOverrides overrides = verificationStorage.get(PaperLevelOverrides.TYPE);
+            if (overrides == null || overrides.isInitialized()) {
+                throw new IOException("Current Paper level overrides could not be verified.");
+            }
+        }
+    }
+
+    private PaperLevelOverrides captureCurrentPaperLevelOverrides(
+            CraftServer craftServer,
+            MinecraftServer server
+    ) throws IOException {
+        if (craftServer.isGlobalTickThread()) {
+            return createCurrentPaperLevelOverrides(server);
+        }
+        if (J.isFolia() && J.isPrimaryThread()) {
+            throw new IOException("Current Paper world data cannot be staged from a Folia region tick thread.");
+        }
+
+        CompletableFuture<PaperLevelOverrides> captured = new CompletableFuture<>();
+        boolean scheduled = J.runGlobal(() -> {
+            try {
+                captured.complete(createCurrentPaperLevelOverrides(server));
+            } catch (Throwable failure) {
+                captured.completeExceptionally(failure);
+            }
+        });
+        if (!scheduled) {
+            throw new IOException("Could not schedule the current Paper level-data snapshot on the global thread.");
+        }
+
+        try {
+            return captured.get(CURRENT_WORLD_DATA_SNAPSHOT_TIMEOUT_SECONDS, TimeUnit.SECONDS);
+        } catch (InterruptedException failure) {
+            Thread.currentThread().interrupt();
+            throw new IOException("Interrupted while capturing current Paper level data.", failure);
+        } catch (ExecutionException failure) {
+            throw new IOException("Could not capture current Paper level data.", failure.getCause());
+        } catch (TimeoutException failure) {
+            throw new IOException("Timed out while capturing current Paper level data.", failure);
+        }
+    }
+
+    private PaperLevelOverrides createCurrentPaperLevelOverrides(MinecraftServer server) throws IOException {
+        if (!(server.getWorldData().overworldData() instanceof PrimaryLevelData primaryLevelData)) {
+            throw new IOException("Paper primary level data is unavailable for current world data staging.");
+        }
+        return PaperLevelOverrides.createFromLiveLevelData(primaryLevelData);
+    }
+
     @Override
     public KMap<Material, List<BlockProperty>> getBlockProperties() {
         KMap<Material, List<BlockProperty>> states = new KMap<>();

adapters/bukkit/nms/v26_2_R1/src/test/java/art/arcane/iris/core/nms/v26_2_R1/NMSBindingCurrentPaperWorldDataContractTest.java

@@ -0,0 +1,92 @@
+package art.arcane.iris.core.nms.v26_2_R1;
+
+import art.arcane.iris.core.nms.INMSBinding;
+import org.junit.Test;
+
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.Proxy;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertTrue;
+
+public class NMSBindingCurrentPaperWorldDataContractTest {
+    @Test
+    public void stagesAllCurrentPaperWorldDataFromLiveServerState() throws Exception {
+        String source = Files.readString(Path.of(System.getProperty("iris.nmsBindingSource")));
+        String writer = section(
+                source,
+                "public void writeCurrentPaperWorldData(",
+                "public KMap<Material, List<BlockProperty>> getBlockProperties()"
+        );
+
+        assertTrue(writer.contains("WorldReplacementSeed.copyWithAuthoritativeSeed("));
+        assertTrue(writer.contains("UUID metadataUuid = UUID.randomUUID()"));
+        assertTrue(writer.contains("new PaperWorldMetadata(metadataUuid)"));
+        assertTrue(writer.contains("captureCurrentPaperLevelOverrides(craftServer, server)"));
+        assertTrue(writer.contains("new SavedDataStorage("));
+        assertTrue(writer.contains("server.getFixerUpper()"));
+        assertTrue(writer.contains("server.registryAccess()"));
+        assertTrue(writer.contains("data/minecraft/world_gen_settings.dat"));
+        assertTrue(writer.contains("data/paper/metadata.dat"));
+        assertTrue(writer.contains("data/paper/level_overrides.dat"));
+        assertTrue(writer.contains("WorldReplacementSeed.readAuthoritativeSeed(targetWorld)"));
+        assertTrue(writer.contains("verificationStorage.get(PaperWorldMetadata.TYPE)"));
+        assertTrue(writer.contains("metadataUuid.equals(metadata.uuid())"));
+        assertTrue(writer.contains("verificationStorage.get(PaperLevelOverrides.TYPE)"));
+        assertTrue(writer.contains("overrides == null || overrides.isInitialized()"));
+        assertTrue(writer.contains("Files.isRegularFile(requiredDataFile, LinkOption.NOFOLLOW_LINKS)"));
+        assertFalse(writer.toLowerCase().contains("migrat"));
+        assertFalse(writer.toLowerCase().contains("fallback"));
+    }
+
+    @Test
+    public void capturesOnlyLiveLevelOverridesOnTheGlobalThread() throws Exception {
+        String source = Files.readString(Path.of(System.getProperty("iris.nmsBindingSource")));
+        String capture = section(
+                source,
+                "private PaperLevelOverrides captureCurrentPaperLevelOverrides(",
+                "private PaperLevelOverrides createCurrentPaperLevelOverrides("
+        );
+        String create = section(
+                source,
+                "private PaperLevelOverrides createCurrentPaperLevelOverrides(",
+                "public KMap<Material, List<BlockProperty>> getBlockProperties()"
+        );
+
+        assertTrue(capture.contains("craftServer.isGlobalTickThread()"));
+        assertTrue(capture.contains("J.isFolia() && J.isPrimaryThread()"));
+        assertTrue(capture.contains("J.runGlobal("));
+        assertTrue(capture.contains("captured.get(CURRENT_WORLD_DATA_SNAPSHOT_TIMEOUT_SECONDS"));
+        assertTrue(capture.contains("Thread.currentThread().interrupt()"));
+        assertTrue(create.contains("PaperLevelOverrides.createFromLiveLevelData(primaryLevelData)"));
+        assertFalse(capture.contains("WorldReplacementSeed"));
+        assertFalse(capture.contains("SavedDataStorage"));
+        assertFalse(capture.contains("Files."));
+    }
+
+    @Test
+    public void unsupportedBindingsRejectCurrentPaperWorldDataStaging() {
+        INMSBinding binding = (INMSBinding) Proxy.newProxyInstance(
+                INMSBinding.class.getClassLoader(),
+                new Class<?>[]{INMSBinding.class},
+                (proxy, method, arguments) -> InvocationHandler.invokeDefault(proxy, method, arguments)
+        );
+
+        UnsupportedOperationException error = assertThrows(
+                UnsupportedOperationException.class,
+                () -> binding.writeCurrentPaperWorldData(Path.of("source"), Path.of("target"), 1L)
+        );
+        assertTrue(error.getMessage().contains("does not support current Paper world data staging"));
+    }
+
+    private static String section(String source, String startMarker, String endMarker) {
+        int start = source.indexOf(startMarker);
+        int end = source.indexOf(endMarker, start);
+        assertTrue("Missing source section starting with " + startMarker, start >= 0);
+        assertTrue("Missing source section ending with " + endMarker, end > start);
+        return source.substring(start, end);
+    }
+}

adapters/bukkit/plugin/src/main/java/art/arcane/iris/core/BukkitWorldReconciler.java

@@ -89,14 +89,17 @@ public final class BukkitWorldReconciler {
 
         DimensionResolution dimensionResolution;
         Long configuredSeed;
+        String configuredWorldName;
         try {
+            configuredWorldName = backend.configuredWorldName(worldKey);
             dimensionResolution = backend.resolveDimension(worldKey);
             configuredSeed = dimensionResolution.succeeded()
-                    ? backend.configuredSeed(IrisWorldStorage.logicalName(worldKey))
+                    ? backend.configuredSeed(configuredWorldName)
                     : null;
         } catch (Throwable failure) {
             dimensionResolution = DimensionResolution.failed(failure);
             configuredSeed = null;
+            configuredWorldName = IrisWorldStorage.logicalName(worldKey);
         }
         if (!dimensionResolution.succeeded()) {
             lease.close();
@@ -106,6 +109,7 @@ public final class BukkitWorldReconciler {
         }
         return loadWithLease(
                 configurationFile,
+                configuredWorldName,
                 worldKey,
                 dimensionResolution.dimension(),
                 configuredSeed,
@@ -137,7 +141,7 @@ public final class BukkitWorldReconciler {
             }
             NamespacedKey worldKey;
             try {
-                worldKey = IrisWorldStorage.keyFromName(worldName);
+                worldKey = backend.worldKeyFromConfiguration(worldName);
             } catch (Throwable failure) {
                 chain = chain.thenApply(results -> {
                     results.add(LoadResult.validationFailure(worldName, failure));
@@ -158,6 +162,7 @@ public final class BukkitWorldReconciler {
             }
             chain = chain.thenCompose(results -> loadConfiguredWorld(
                             ServerProperties.BUKKIT_YML,
+                            worldName,
                             worldKey,
                             dimension,
                             seed)
@@ -176,6 +181,7 @@ public final class BukkitWorldReconciler {
 
     private CompletableFuture<LoadResult> loadConfiguredWorld(
             File configurationFile,
+            String configuredWorldName,
             NamespacedKey worldKey,
             String dimension,
             Long seed
@@ -187,7 +193,7 @@ public final class BukkitWorldReconciler {
             return CompletableFuture.completedFuture(LoadResult.busy(worldKey, failure));
         }
 
-        return loadWithLease(configurationFile, worldKey, dimension, seed, lease);
+        return loadWithLease(configurationFile, configuredWorldName, worldKey, dimension, seed, lease);
     }
 
     private LifecycleOperationCoordinator.Lease acquireWorldLoad(NamespacedKey worldKey) {
@@ -199,6 +205,7 @@ public final class BukkitWorldReconciler {
 
     private CompletableFuture<LoadResult> loadWithLease(
             File configurationFile,
+            String configuredWorldName,
             NamespacedKey worldKey,
             String dimension,
             Long seed,
@@ -214,11 +221,10 @@ public final class BukkitWorldReconciler {
         }
 
         BukkitWorldConfiguration.Registration registration;
-        String worldName = IrisWorldStorage.logicalName(worldKey);
         try {
             registration = BukkitWorldConfiguration.register(
                     configurationFile,
-                    worldName,
+                    configuredWorldName,
                     dimension,
                     seed);
         } catch (Throwable failure) {
@@ -250,7 +256,7 @@ public final class BukkitWorldReconciler {
                     try {
                         boolean rolledBack = BukkitWorldConfiguration.removeIfMatching(
                                 configurationFile,
-                                worldName,
+                                configuredWorldName,
                                 dimension,
                                 seed);
                         return new LoadResult(settled, registration, true, rolledBack, null);
@@ -426,6 +432,10 @@ public final class BukkitWorldReconciler {
 
         Long configuredSeed(String worldName);
 
+        String configuredWorldName(NamespacedKey worldKey);
+
+        NamespacedKey worldKeyFromConfiguration(String configuredWorldName);
+
         Optional<World> loadedWorld(NamespacedKey worldKey);
 
         CompletableFuture<World> createWorld(NamespacedKey worldKey, String dimension, Long seed);
@@ -667,6 +677,19 @@ public final class BukkitWorldReconciler {
             return IrisWorlds.readBukkitWorldSeed(worldName);
         }
 
+        @Override
+        public String configuredWorldName(NamespacedKey worldKey) {
+            return IrisWorldStorage.configuredWorldName(worldKey, IrisWorldStorage.levelRoot().getName());
+        }
+
+        @Override
+        public NamespacedKey worldKeyFromConfiguration(String configuredWorldName) {
+            return IrisWorldStorage.keyFromConfiguredWorldName(
+                    configuredWorldName,
+                    IrisWorldStorage.levelRoot().getName()
+            );
+        }
+
         @Override
         public Optional<World> loadedWorld(NamespacedKey worldKey) {
             return WorldIdentity.resolve(worldKey);

adapters/bukkit/plugin/src/main/java/art/arcane/iris/core/IrisWorldGeneratorResolver.java

@@ -165,7 +165,8 @@ public final class IrisWorldGeneratorResolver {
 
     @Nullable
     public static IrisDimension loadDimension(@NonNull String worldName, @NonNull String id) {
-        File pack = IrisWorldStorage.packRoot(IrisWorldStorage.keyFromName(worldName));
+        NamespacedKey worldKey = configuredWorldKey(worldName, IrisWorldStorage.levelRoot().getName());
+        File pack = IrisWorldStorage.packRoot(worldKey);
         IrisDimension dimension = pack.isDirectory() ? IrisData.get(pack).getDimensionLoader().load(id) : null;
         if (dimension == null) dimension = IrisData.loadAnyDimension(id, null);
         if (dimension == null) {
@@ -182,6 +183,10 @@ public final class IrisWorldGeneratorResolver {
         return dimension;
     }
 
+    static NamespacedKey configuredWorldKey(String worldName, String levelName) {
+        return IrisWorldStorage.keyFromConfiguredWorldName(worldName, levelName);
+    }
+
     /**
      * Resolves the biome provider for a world, falling back to the supplied Bukkit default when
      * Iris has nothing staged.
@@ -212,7 +217,7 @@ public final class IrisWorldGeneratorResolver {
         if (dim == null) {
             throw new RuntimeException("Can't find dimension " + id + "!");
         }
-        NamespacedKey worldKey = IrisWorldStorage.keyFromName(worldName);
+        NamespacedKey worldKey = configuredWorldKey(worldName, IrisWorldStorage.levelRoot().getName());
         File snapshotRoot = IrisWorldStorage.packRoot(worldKey);
         File dimensionPackRoot = dim.getLoader().getDataFolder();
         String packName = dimensionPackRoot.getName();

adapters/bukkit/plugin/src/main/java/art/arcane/iris/core/PendingWorldReplacementManager.java

@@ -13,6 +13,7 @@ import art.arcane.iris.core.lifecycle.WorldReplacementFilesystem.ReplacementPath
 import art.arcane.iris.core.lifecycle.WorldReplacementJournal;
 import art.arcane.iris.core.lifecycle.WorldReplacementJournal.Phase;
 import art.arcane.iris.core.lifecycle.WorldReplacementJournal.Transaction;
+import art.arcane.iris.core.lifecycle.WorldReplacementSeed;
 import art.arcane.iris.core.pack.PackValidationRegistry;
 import art.arcane.iris.core.service.StudioSVC;
 import art.arcane.iris.core.tools.IrisToolbelt;
@@ -33,7 +34,6 @@ import org.bukkit.event.world.WorldLoadEvent;
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
-import java.nio.file.LinkOption;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.HashSet;
@@ -56,19 +56,10 @@ public final class PendingWorldReplacementManager implements Listener {
     }
 
     public NamespacedKey resolveRequestedWorldKey(String requestedName) {
-        String requested = Objects.requireNonNull(requestedName, "requestedName").trim();
-        if (requested.isEmpty()) {
-            throw new IllegalArgumentException("World name cannot be empty.");
-        }
-        if (requested.contains("/") || requested.contains("\\") || requested.contains("..")) {
-            throw new IllegalArgumentException("World name must be a safe single path segment.");
-        }
-        NamespacedKey worldKey = requested.contains(":")
-                ? NamespacedKey.fromString(requested.toLowerCase(Locale.ENGLISH))
-                : IrisWorldStorage.keyFromName(requested);
-        if (worldKey == null) {
-            throw new IllegalArgumentException("World identifier is invalid: " + requestedName);
-        }
+        NamespacedKey worldKey = IrisWorldStorage.replacementKeyFromName(
+                requestedName,
+                IrisWorldStorage.levelRoot().getName()
+        );
         ExactWorldSlotPathPolicy.resolve(IrisWorldStorage.levelRoot().toPath(), toWorldSlotKey(worldKey));
         return worldKey;
     }
@@ -76,14 +67,13 @@ public final class PendingWorldReplacementManager implements Listener {
     public synchronized StagedReplacement stageReplacement(
             VolmitSender sender,
             NamespacedKey worldKey,
-            IrisDimension dimension,
-            long seed
+            IrisDimension dimension
     ) throws IOException {
         VolmitSender requiredSender = Objects.requireNonNull(sender, "sender");
         NamespacedKey requiredWorldKey = Objects.requireNonNull(worldKey, "worldKey");
         WorldSlotKey requiredWorldSlotKey = toWorldSlotKey(requiredWorldKey);
         IrisDimension requiredDimension = Objects.requireNonNull(dimension, "dimension");
-        IrisStartupValidation.requireWorldCreationReady();
+        IrisStartupValidation.requireWorldReplacementStagingReady();
         if (!WorldReplacementBootstrapMarker.wasBootstrappedThisProcess()) {
             throw new IOException("Exact world replacement requires a full Paper-family startup bootstrap.");
         }
@@ -97,18 +87,19 @@ public final class PendingWorldReplacementManager implements Listener {
             if (findTransaction(requiredWorldSlotKey) != null) {
                 throw new IOException("A replacement is already pending for " + requiredWorldKey + ".");
             }
-            ExactWorldSlotPathPolicy.Target target = prepareTarget(requiredWorldSlotKey);
+            ExactWorldSlotPathPolicy.Target target = resolveTarget(requiredWorldSlotKey);
             requireCompatibleEnvironment(target.slotKind(), requiredDimension.getEnvironment());
-            long effectiveSeed = resolveEffectiveSeed(target.slotKind(), seed);
+            requireVanillaSlotEnabled(target.slotKind());
+            UUID transactionId = UUID.randomUUID();
+            ReplacementPaths paths = WorldReplacementFilesystem.paths(target, transactionId);
+            WorldReplacementFilesystem.requireExistingTarget(paths);
+            long effectiveSeed = WorldReplacementSeed.readAuthoritativeSeed(paths.target());
             String worldName = WorldReplacementJournal.logicalWorldName(target.levelRoot(), requiredWorldSlotKey);
             DatapackInstallResult datapacks = ServerConfigurator.installDataPacksIfChanged(true);
             if (!datapacks.succeeded()) {
                 throw new IOException("Iris could not compile the dimension datapacks.");
             }
 
-            UUID transactionId = UUID.randomUUID();
-            ReplacementPaths paths = WorldReplacementFilesystem.paths(target, transactionId);
-            WorldReplacementFilesystem.requireExistingTarget(paths);
             boolean targetPresent = true;
             WorldGeneratorSnapshot originalConfiguration = BukkitWorldConfiguration.snapshot(
                     ServerProperties.BUKKIT_YML,
@@ -435,23 +426,8 @@ public final class PendingWorldReplacementManager implements Listener {
         }
     }
 
-    private ExactWorldSlotPathPolicy.Target prepareTarget(WorldSlotKey worldKey) throws IOException {
-        Path levelRoot = IrisWorldStorage.levelRoot().toPath();
-        ExactWorldSlotPathPolicy.Target target = ExactWorldSlotPathPolicy.resolve(levelRoot, worldKey);
-        Path dimensions = target.levelRoot().resolve("dimensions");
-        createDirectoryIfMissing(dimensions);
-        createDirectoryIfMissing(target.namespaceRoot());
-        return ExactWorldSlotPathPolicy.resolve(levelRoot, worldKey);
-    }
-
-    private static void createDirectoryIfMissing(Path directory) throws IOException {
-        if (Files.exists(directory, LinkOption.NOFOLLOW_LINKS)) {
-            if (Files.isSymbolicLink(directory) || !Files.isDirectory(directory, LinkOption.NOFOLLOW_LINKS)) {
-                throw new IOException("World storage parent is unsafe: " + directory);
-            }
-            return;
-        }
-        Files.createDirectory(directory);
+    private static ExactWorldSlotPathPolicy.Target resolveTarget(WorldSlotKey worldKey) {
+        return ExactWorldSlotPathPolicy.resolve(IrisWorldStorage.levelRoot().toPath(), worldKey);
     }
 
     private Transaction findTransaction(NamespacedKey worldKey) throws IOException {
@@ -510,7 +486,7 @@ public final class PendingWorldReplacementManager implements Listener {
         }
     }
 
-    private static void requireCompatibleEnvironment(SlotKind slotKind, IrisEnvironment environment) {
+    static void requireCompatibleEnvironment(SlotKind slotKind, IrisEnvironment environment) {
         IrisEnvironment expected = switch (slotKind) {
             case VANILLA_OVERWORLD -> IrisEnvironment.NORMAL;
             case VANILLA_NETHER -> IrisEnvironment.NETHER;
@@ -524,62 +500,58 @@ public final class PendingWorldReplacementManager implements Listener {
     }
 
     /**
-     * Captures the primary level context on the main thread at startup. resolveEffectiveSeed
-     * reads this snapshot so staging never blocks on a main-thread hop while holding the
-     * manager monitor — that inversion froze the server for the full 30s hop timeout whenever
-     * another world loaded during staging. The context is stable for the process lifetime:
-     * slot replacements only commit across a restart.
+     * Captures vanilla-slot availability on the main thread at startup so staging never blocks
+     * on a main-thread hop while holding the manager monitor. The context is stable for the
+     * process lifetime because slot replacements only commit across a restart.
      */
     public void captureVanillaLevelContext() {
         try {
             vanillaLevelContext = new VanillaLevelContext(
-                    WorldIdentity.resolve(NamespacedKey.minecraft("overworld"))
-                            .orElseThrow(() -> new IllegalStateException("The configured primary world is not loaded."))
-                            .getSeed(),
                     Iris.instance.getServer().getAllowNether(),
                     Iris.instance.getServer().getAllowEnd()
             );
         } catch (Throwable failure) {
-            Iris.debug("Could not capture the primary level context yet: " + detail(failure));
+            Iris.debug("Could not capture vanilla-slot availability yet: " + detail(failure));
         }
     }
 
-    private static long resolveEffectiveSeed(SlotKind slotKind, long requestedSeed) throws IOException {
-        if (slotKind == SlotKind.IRIS_MANAGED) {
-            return requestedSeed;
+    private static void requireVanillaSlotEnabled(SlotKind slotKind) throws IOException {
+        if (slotKind != SlotKind.VANILLA_NETHER && slotKind != SlotKind.VANILLA_END) {
+            return;
         }
         VanillaLevelContext context = vanillaLevelContext;
         if (context == null) {
             context = resolveVanillaLevelContext();
             vanillaLevelContext = context;
         }
-        if (slotKind == SlotKind.VANILLA_NETHER && !context.allowNether()) {
+        requireVanillaSlotEnabled(slotKind, context.allowNether(), context.allowEnd());
+    }
+
+    static void requireVanillaSlotEnabled(SlotKind slotKind, boolean allowNether, boolean allowEnd)
+            throws IOException {
+        if (slotKind == SlotKind.VANILLA_NETHER && !allowNether) {
             throw new IOException("allow-nether must be true before the vanilla Nether can be replaced.");
         }
-        if (slotKind == SlotKind.VANILLA_END && !context.allowEnd()) {
+        if (slotKind == SlotKind.VANILLA_END && !allowEnd) {
             throw new IOException("Bukkit allow-end must be true before the vanilla End can be replaced.");
         }
-        return context.seed();
     }
 
     private static VanillaLevelContext resolveVanillaLevelContext() throws IOException {
         CompletableFuture<VanillaLevelContext> contextFuture = J.sfut(() -> new VanillaLevelContext(
-                WorldIdentity.resolve(NamespacedKey.minecraft("overworld"))
-                        .orElseThrow(() -> new IllegalStateException("The configured primary world is not loaded."))
-                        .getSeed(),
                 Iris.instance.getServer().getAllowNether(),
                 Iris.instance.getServer().getAllowEnd()
         ));
         if (contextFuture == null) {
-            throw new IOException("Could not schedule primary level-seed resolution.");
+            throw new IOException("Could not schedule vanilla-slot availability resolution.");
         }
         try {
             return contextFuture.get(30L, TimeUnit.SECONDS);
         } catch (InterruptedException failure) {
             Thread.currentThread().interrupt();
-            throw new IOException("Primary level-seed resolution was interrupted.", failure);
+            throw new IOException("Vanilla-slot availability resolution was interrupted.", failure);
         } catch (ExecutionException | TimeoutException failure) {
-            throw new IOException("Could not resolve the authoritative primary level seed.", failure);
+            throw new IOException("Could not resolve vanilla-slot availability.", failure);
         }
     }
 
@@ -628,7 +600,7 @@ public final class PendingWorldReplacementManager implements Listener {
 
     private static volatile VanillaLevelContext vanillaLevelContext;
 
-    private record VanillaLevelContext(long seed, boolean allowNether, boolean allowEnd) {
+    private record VanillaLevelContext(boolean allowNether, boolean allowEnd) {
     }
 
     private static final class RestartBoundaryRequired extends IOException {

adapters/bukkit/plugin/src/main/java/art/arcane/iris/core/commands/CommandIris.java

@@ -33,6 +33,7 @@ import art.arcane.iris.core.lifecycle.IrisWorldRemovalService;
 import art.arcane.iris.core.lifecycle.LifecycleOperationCoordinator;
 import art.arcane.iris.core.lifecycle.WorldLifecycleService;
 import art.arcane.iris.core.loader.IrisData;
+import art.arcane.iris.core.nms.INMS;
 import art.arcane.iris.core.pack.AtomicDirectoryPublisher;
 import art.arcane.iris.core.pack.PackDownloader;
 import art.arcane.iris.core.pack.PackDirectoryResolver;
@@ -52,7 +53,6 @@ import art.arcane.volmlib.util.director.annotations.Param;
 import art.arcane.volmlib.util.director.exceptions.DirectorParsingException;
 import art.arcane.iris.util.common.director.specialhandlers.NullablePlayerHandler;
 import art.arcane.iris.util.common.format.C;
-import art.arcane.iris.util.common.misc.ServerProperties;
 import art.arcane.iris.util.common.plugin.VolmitSender;
 import art.arcane.iris.util.common.scheduling.J;
 import org.bukkit.Bukkit;
@@ -62,28 +62,17 @@ import org.bukkit.World;
 import org.bukkit.entity.Player;
 
 import java.io.File;
-import java.io.FileInputStream;
-import java.io.FileOutputStream;
 import java.io.IOException;
-import java.nio.file.AtomicMoveNotSupportedException;
-import java.nio.file.FileAlreadyExistsException;
 import java.nio.file.Files;
-import java.nio.file.LinkOption;
 import java.nio.file.Path;
-import java.nio.file.StandardCopyOption;
-import java.util.Comparator;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Locale;
-import java.util.Objects;
-import java.util.Properties;
 import java.util.Set;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.concurrent.atomic.AtomicReference;
-import java.util.stream.Stream;
 
 import static art.arcane.iris.util.common.misc.ServerProperties.BUKKIT_YML;
 import static org.bukkit.Bukkit.getServer;
@@ -109,7 +98,6 @@ public class CommandIris implements DirectorExecutor {
     private CommandPack pack;
     private CommandFind find;
     private CommandDatapack datapack;
-    private static final AtomicReference<Thread> mainWorld = new AtomicReference<>();
     VolmitSender sender = Iris.getSender();
 
     @Director(description = "Create a new world", descriptionKey = "iris.director.commandiris.director.create_new_world", aliases = {"c"})
@@ -124,29 +112,17 @@ public class CommandIris implements DirectorExecutor {
             )
             String type,
             @Param(description = "The seed to generate the world with", descriptionKey = "iris.director.commandiris.param.seed_generate_world_with", defaultValue = "1337")
-            long seed,
-            @Param(aliases = "main-world", description = "Whether or not to automatically use this world as the main world", descriptionKey = "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world", defaultValue = "false")
-            boolean main,
-            @Param(name = "overwrite", aliases = "force", description = "Replace the exact existing world slot on the next restart", descriptionKey = "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart", defaultValue = "false")
-            boolean overwrite
+            long seed
     ) {
         NamespacedKey worldKey;
         try {
-            if (overwrite) {
-                worldKey = Iris.instance.pendingWorldReplacements().resolveRequestedWorldKey(name);
-            } else {
             worldKey = IrisWorldStorage.managedKeyFromName(name);
             IrisWorldStorage.requireSafeManagedDimensionRoot(worldKey);
-            }
         } catch (IllegalArgumentException e) {
             sender().sendMessage(C.RED + e.getMessage());
             return;
         }
         String worldName = IrisWorldStorage.logicalName(worldKey);
-        if (overwrite && main && !NamespacedKey.minecraft("overworld").equals(worldKey)) {
-            sender().sendMessage(C.RED + "overwrite=true with main=true must target the configured main-world name.");
-            return;
-        }
         if (worldName.equalsIgnoreCase("iris")) {
             sender().sendMessage(IrisLanguage.text(BukkitCommandMessagesExtended.COMMAND_IRIS_YOU_CANNOT_USE_WORLD_NAME_IRIS_CREATING_WORLDS_AS_IRIS));
             sender().sendMessage(IrisLanguage.text(BukkitCommandMessagesExtended.COMMAND_IRIS_MAY_WE_SUGGEST_NAME_IRISWORLD_INSTEAD));
@@ -159,7 +135,7 @@ public class CommandIris implements DirectorExecutor {
             return;
         }
 
-        if (!overwrite && IrisWorldStorage.dimensionRoot(worldName).exists()) {
+        if (IrisWorldStorage.dimensionRoot(worldName).exists()) {
             sender().sendMessage(IrisLanguage.text(BukkitCommandMessagesExtended.COMMAND_IRIS_THAT_FOLDER_ALREADY_EXISTS));
             return;
         }
@@ -177,31 +153,13 @@ public class CommandIris implements DirectorExecutor {
             return;
         }
 
-        if (overwrite) {
-            try {
-                PendingWorldReplacementManager.StagedReplacement staged = Iris.instance
-                        .pendingWorldReplacements()
-                        .stageReplacement(sender(), worldKey, dimension, seed);
-                if (staged.seed() != seed) {
-                    sender().sendMessage(C.YELLOW + "Exact vanilla slots preserve the shared level seed; using "
-                            + staged.seed() + " instead of " + seed + ".");
-                }
-                sender().sendMessage(C.GREEN + "Staged Iris replacement for " + staged.worldKey()
-                        + ". Restart once to publish it. The current dimension is retained until Iris verifies the replacement.");
-            } catch (Throwable failure) {
-                Iris.reportError("Failed to stage Iris world replacement for " + worldKey + ".", failure);
-                String detail = failure.getMessage() == null || failure.getMessage().isBlank()
-                        ? failure.getClass().getSimpleName()
-                        : failure.getMessage();
-                sender().sendMessage(C.RED + "Could not stage the world replacement: " + detail);
-            }
+        if (J.isFolia()) {
+            boolean staged = stageFoliaWorldCreation(worldName, dimension, seed);
+            if (!staged) {
                 return;
             }
-
-        if (J.isFolia()) {
-            if (stageFoliaWorldCreation(worldName, dimension, seed, main)) {
-                sender().sendMessage(IrisLanguage.text(BukkitCommandMessagesExtended.COMMAND_IRIS_WORLD_STAGING_COMPLETED_RESTART_SERVER_GENERATE_LOAD, MessageArgument.untrusted("worldName", worldName)));
-            }
+            sender().sendMessage(IrisLanguage.text(BukkitCommandMessagesExtended.COMMAND_IRIS_WORLD_STAGING_COMPLETED_RESTARTING_SERVER_GENERATE_LOAD, MessageArgument.untrusted("worldName", worldName)));
+            ServerConfigurator.restart("Iris staged Folia world \"" + worldName + "\" for startup.");
             return;
         }
 
@@ -213,12 +171,6 @@ public class CommandIris implements DirectorExecutor {
                     .sender(sender())
                     .studio(false)
                     .create();
-            if (main) {
-                Runtime.getRuntime().addShutdownHook(mainWorld.updateAndGet(old -> {
-                    if (old != null) Runtime.getRuntime().removeShutdownHook(old);
-                    return new Thread(() -> updateMainWorld(worldName));
-                }));
-            }
         } catch (Throwable e) {
             if (reportExpectedCreationInterruption(e)) {
                 return;
@@ -229,207 +181,65 @@ public class CommandIris implements DirectorExecutor {
         }
 
         sender().sendMessage(IrisLanguage.text(BukkitCommandMessagesExtended.COMMAND_IRIS_SUCCESSFULLY_CREATED_YOUR_WORLD));
-        if (main) sender().sendMessage(IrisLanguage.text(BukkitCommandMessagesExtended.COMMAND_IRIS_YOUR_WORLD_WILL_AUTOMATICALLY_BE_SET_AS_MAIN_WORLD_WHEN));
     }
 
-    private boolean updateMainWorld(String newName) {
-        LifecycleOperationCoordinator.Lease lease;
+    @Director(
+            description = "Replace an existing world with Iris generation on the next restart",
+            descriptionKey = "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart",
+            aliases = {"override", "overwrite"}
+    )
+    public void replace(
+            @Param(
+                    name = "target",
+                    aliases = "world-name",
+                    description = "The exact existing world slot to replace",
+                    descriptionKey = "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart"
+            )
+            String target,
+            @Param(
+                    aliases = {"dimension", "pack"},
+                    description = "The dimension/pack to replace the world with",
+                    defaultValue = "default",
+                    customHandler = PackDimensionTypeHandler.class
+            )
+            String type
+    ) {
+        NamespacedKey worldKey;
         try {
-            lease = LifecycleOperationCoordinator.get().acquire(
-                    LifecycleOperationCoordinator.Domain.WORLD_MUTATION,
-                    LifecycleOperationCoordinator.OperationKind.WORLD_PROMOTE,
-                    newName
-            );
-        } catch (LifecycleOperationCoordinator.BusyException e) {
-            Iris.error("Could not promote Iris world \"" + newName + "\": " + e.getMessage());
-            return false;
-        }
-
-        try {
-            return updateMainWorldUnderLease(newName);
-        } finally {
-            lease.close();
-        }
-    }
-
-    private boolean updateMainWorldUnderLease(String newName) {
-        try {
-            File oldLevelRoot = IrisWorldStorage.levelRoot();
-            File worldContainer = oldLevelRoot.getParentFile();
-            if (worldContainer == null) {
-                throw new IllegalStateException("Current level folder has no world container.");
-            }
-            Properties data = new Properties();
-            try (FileInputStream in = new FileInputStream(ServerProperties.SERVER_PROPERTIES)) {
-                data.load(in);
-            }
-
-            File sourceDimensionRoot = IrisWorldStorage.dimensionRoot(IrisWorldStorage.keyFromName(newName));
-            if (!sourceDimensionRoot.isDirectory()) {
-                throw new IllegalStateException("Source dimension folder does not exist: " + sourceDimensionRoot.getAbsolutePath());
-            }
-
-            File newLevelRoot = new File(worldContainer, newName);
-            World sourceWorld = WorldIdentity.resolve(IrisWorldStorage.keyFromName(newName)).orElse(null);
-            Long stagedSeed = IrisWorlds.readBukkitWorldSeed(newName);
-            if (sourceWorld == null && stagedSeed == null) {
-                throw new IllegalStateException("Cannot determine the promoted world's seed.");
-            }
-            long promotedSeed = sourceWorld == null ? stagedSeed : sourceWorld.getSeed();
-            data.setProperty("level-name", newName);
-            data.setProperty("level-seed", Long.toString(promotedSeed));
-
-            try (MainWorldPublication publication = publishMainWorldFiles(
-                    oldLevelRoot.toPath(),
-                    sourceDimensionRoot.toPath(),
-                    newLevelRoot.toPath()
-            )) {
-                writeServerPropertiesAtomically(ServerProperties.SERVER_PROPERTIES.toPath(), data);
-                publication.commit();
-            }
-            synchronized (ServerProperties.DATA) {
-                ServerProperties.DATA.clear();
-                ServerProperties.DATA.putAll(data);
-            }
-            return true;
-        } catch (Throwable e) {
-            Iris.error("Failed to update server.properties main world to \"" + newName + "\"");
-            Iris.reportError(e);
-            return false;
-        }
-    }
-
-    static MainWorldPublication publishMainWorldFiles(
-            Path currentLevelRoot,
-            Path sourceDimensionRoot,
-            Path targetLevelRoot
-    ) throws IOException {
-        Path current = Objects.requireNonNull(currentLevelRoot, "currentLevelRoot").toAbsolutePath().normalize();
-        Path sourceDimension = Objects.requireNonNull(sourceDimensionRoot, "sourceDimensionRoot").toAbsolutePath().normalize();
-        Path target = Objects.requireNonNull(targetLevelRoot, "targetLevelRoot").toAbsolutePath().normalize();
-        Path worldContainer = current.getParent();
-        Path sourceNamespace = current.resolve("dimensions/iris");
-        if (worldContainer == null || !Objects.equals(target.getParent(), worldContainer)) {
-            throw new IOException("Promoted main world must be a direct child of the world container.");
-        }
-        if (!Objects.equals(sourceDimension.getParent(), sourceNamespace)) {
-            throw new IOException("Promoted source must be a direct Iris dimension.");
-        }
-        if (Objects.equals(current, target)) {
-            throw new IOException("Promoted main world cannot replace the current main world.");
-        }
-        if (Files.isSymbolicLink(worldContainer)
-                || Files.isSymbolicLink(current)
-                || !Files.isDirectory(current, LinkOption.NOFOLLOW_LINKS)) {
-            throw new IOException("Current world storage is missing or unsafe.");
-        }
-        if (Files.isSymbolicLink(sourceDimension)
-                || !Files.isDirectory(sourceDimension, LinkOption.NOFOLLOW_LINKS)) {
-            throw new IOException("Promoted Iris dimension is missing or unsafe: " + sourceDimension);
-        }
-        requireAbsentMainWorldTarget(target);
-
-        Path stage = Files.createTempDirectory(worldContainer, "." + target.getFileName() + ".promoting-");
-        boolean published = false;
-        try {
-            for (String subdirectory : List.of("data", "datapacks", "players")) {
-                Path source = current.resolve(subdirectory);
-                if (!Files.exists(source, LinkOption.NOFOLLOW_LINKS) && !Files.isSymbolicLink(source)) {
-                    continue;
-                }
-                copyWorldTree(source, stage.resolve(subdirectory));
-            }
-
-            Path targetDimension = IrisWorldStorage.dimensionRoot(
-                    stage.toFile(),
-                    NamespacedKey.minecraft("overworld")
-            ).toPath();
-            copyWorldTree(sourceDimension, targetDimension);
-            requireAbsentMainWorldTarget(target);
-            Files.move(stage, target);
-            published = true;
-            return new MainWorldPublication(target);
-        } finally {
-            if (!published) {
-                AtomicDirectoryPublisher.deleteTree(stage);
-            }
-        }
-    }
-
-    private static void requireAbsentMainWorldTarget(Path target) throws IOException {
-        if (Files.exists(target, LinkOption.NOFOLLOW_LINKS) || Files.isSymbolicLink(target)) {
-            throw new FileAlreadyExistsException("Main-world target already exists: " + target);
-        }
-    }
-
-    private static void copyWorldTree(Path source, Path target) throws IOException {
-        if (Files.isSymbolicLink(source)) {
-            throw new IOException("World data contains a symbolic link: " + source);
-        }
-        if (Files.isRegularFile(source, LinkOption.NOFOLLOW_LINKS)) {
-            Files.createDirectories(target.getParent());
-            Files.copy(source, target, StandardCopyOption.COPY_ATTRIBUTES);
+            worldKey = Iris.instance.pendingWorldReplacements().resolveRequestedWorldKey(target);
+        } catch (IllegalArgumentException e) {
+            sender().sendMessage(C.RED + e.getMessage());
             return;
         }
-        if (!Files.isDirectory(source, LinkOption.NOFOLLOW_LINKS)) {
-            throw new IOException("World data contains an unsupported entry: " + source);
-        }
-        try (Stream<Path> entries = Files.walk(source)) {
-            for (Path entry : entries.sorted(Comparator.naturalOrder()).toList()) {
-                if (Files.isSymbolicLink(entry)) {
-                    throw new IOException("World data contains a symbolic link: " + entry);
-                }
-                Path destination = target.resolve(source.relativize(entry)).normalize();
-                if (!destination.startsWith(target)) {
-                    throw new IOException("World data escapes its promotion stage: " + entry);
-                }
-                if (Files.isDirectory(entry, LinkOption.NOFOLLOW_LINKS)) {
-                    Files.createDirectories(destination);
-                } else if (Files.isRegularFile(entry, LinkOption.NOFOLLOW_LINKS)) {
-                    Files.createDirectories(destination.getParent());
-                    Files.copy(entry, destination, StandardCopyOption.COPY_ATTRIBUTES);
-                } else {
-                    throw new IOException("World data contains an unsupported entry: " + entry);
-                }
+
+        String resolvedType = type.equalsIgnoreCase("default")
+                ? IrisSettings.get().getGenerator().getDefaultWorldType()
+                : type;
+        IrisDimension dimension = IrisToolbelt.getDimension(resolvedType);
+        if (dimension == null) {
+            sender().sendMessage("Could not find dimension '" + resolvedType + "'.");
+            sender().sendMessage(IrisLanguage.text(BukkitCommandMessagesExtended.COMMAND_IRIS_TRY_ONE_OVERWORLD_VANILLA_FLAT_THEEND));
+            sender().sendMessage("Install its pack with " + PackDownloader.downloadCommandFor(resolvedType)
+                    + " and restart the server.");
+            return;
         }
+
+        try {
+            PendingWorldReplacementManager.StagedReplacement staged = Iris.instance
+                    .pendingWorldReplacements()
+                    .stageReplacement(sender(), worldKey, dimension);
+            sender().sendMessage(C.GREEN + "Staged Iris replacement for " + staged.worldKey()
+                    + ". Restart once to publish it. The current dimension is retained until Iris verifies the replacement.");
+        } catch (Throwable failure) {
+            Iris.reportError("Failed to stage Iris world replacement for " + worldKey + ".", failure);
+            String detail = failure.getMessage() == null || failure.getMessage().isBlank()
+                    ? failure.getClass().getSimpleName()
+                    : failure.getMessage();
+            sender().sendMessage(C.RED + "Could not stage the world replacement: " + detail);
         }
     }
 
-    private static void writeServerPropertiesAtomically(Path propertiesFile, Properties data) throws IOException {
-        Path target = propertiesFile.toAbsolutePath().normalize();
-        Path parent = target.getParent();
-        if (parent == null) {
-            throw new IOException("server.properties has no parent directory.");
-        }
-        Path stage = Files.createTempFile(parent, ".server.properties.promoting-", ".tmp");
-        IOException operationFailure = null;
-        try {
-            try (FileOutputStream out = new FileOutputStream(stage.toFile())) {
-                data.store(out, null);
-                out.getFD().sync();
-            }
-            try {
-                Files.move(stage, target, StandardCopyOption.ATOMIC_MOVE, StandardCopyOption.REPLACE_EXISTING);
-            } catch (AtomicMoveNotSupportedException e) {
-                Files.move(stage, target, StandardCopyOption.REPLACE_EXISTING);
-            }
-        } catch (IOException e) {
-            operationFailure = e;
-            throw e;
-        } finally {
-            try {
-                Files.deleteIfExists(stage);
-            } catch (IOException cleanupFailure) {
-                if (operationFailure != null) {
-                    operationFailure.addSuppressed(cleanupFailure);
-                } else {
-                    throw cleanupFailure;
-                }
-            }
-        }
-    }
-
-    private boolean stageFoliaWorldCreation(String name, IrisDimension dimension, long seed, boolean main) {
+    private boolean stageFoliaWorldCreation(String name, IrisDimension dimension, long seed) {
         try {
             IrisStartupValidation.requireWorldCreationReady();
             PackValidationRegistry.requireLoadable(
@@ -441,6 +251,7 @@ public class CommandIris implements DirectorExecutor {
         NamespacedKey worldKey = IrisWorldStorage.managedKeyFromName(name);
         LifecycleOperationCoordinator.Lease worldLease = null;
         File worldFolder = IrisWorldStorage.requireSafeManagedDimensionRoot(worldKey);
+        Path stagedWorld = null;
         try {
             LifecycleOperationCoordinator coordinator = LifecycleOperationCoordinator.get();
             worldLease = coordinator.acquire(
@@ -459,53 +270,68 @@ public class CommandIris implements DirectorExecutor {
                 sender().sendMessage(C.RED + "Failed to compile the Iris datapack. No world files were staged.");
                 return false;
             }
-            IrisDimension installed = Iris.service(StudioSVC.class).installIntoWorld(sender(), dimension, worldFolder);
+
+            Path targetWorld = worldFolder.toPath().toAbsolutePath().normalize();
+            Path namespaceRoot = targetWorld.getParent();
+            if (namespaceRoot == null) {
+                throw new IOException("Iris world target has no namespace directory: " + targetWorld);
+            }
+            Files.createDirectories(namespaceRoot);
+            stagedWorld = Files.createTempDirectory(namespaceRoot, ".iris-create-" + worldKey.getKey() + "-");
+            Path sourceOverworld = IrisWorldStorage.dimensionRoot(
+                    IrisWorldStorage.levelRoot(),
+                    NamespacedKey.minecraft("overworld")
+            ).toPath();
+            INMS.get().writeCurrentPaperWorldData(sourceOverworld, stagedWorld, seed);
+
+            IrisDimension installed = Iris.service(StudioSVC.class).installIntoWorld(
+                    sender(),
+                    dimension,
+                    stagedWorld.toFile()
+            );
             if (installed == null) {
                 sender().sendMessage(IrisLanguage.text(BukkitCommandMessagesExtended.COMMAND_IRIS_FAILED_STAGE_WORLD_FILES_DIMENSION, MessageArgument.untrusted("value", dimension.getLoadKey())));
-                deleteDirectorySafely(worldFolder);
                 return false;
             }
 
-            if (!registerWorldInBukkitYml(name, dimension.getLoadKey(), seed)) {
-                deleteDirectorySafely(worldFolder);
-                return false;
-            }
-
-            if (main) {
-                if (updateMainWorldUnderLease(name)) {
-                    sender().sendMessage(IrisLanguage.text(BukkitCommandMessagesExtended.COMMAND_IRIS_UPDATED_SERVER_PROPERTIES_LEVEL_NAME, MessageArgument.untrusted("name", name)));
-                } else {
-                    sender().sendMessage(IrisLanguage.text(BukkitCommandMessagesExtended.COMMAND_IRIS_WORLD_WAS_STAGED_BUT_FAILED_UPDATE_SERVER_PROPERTIES_MAIN_WORLD));
-                    try {
-                        BukkitWorldConfiguration.remove(BUKKIT_YML, name);
-                    } catch (IOException e) {
-                        Iris.reportError("Failed to roll back bukkit.yml after main-world staging failed.", e);
-                    }
-                    deleteDirectorySafely(worldFolder);
+            try (AtomicDirectoryPublisher.Publication publication = AtomicDirectoryPublisher.publishAbsent(
+                    stagedWorld,
+                    targetWorld
+            )) {
+                stagedWorld = null;
+                if (!registerWorldInBukkitYml(worldKey, dimension.getLoadKey(), seed)) {
                     return false;
                 }
+                publication.commit();
             }
 
             sender().sendMessage(IrisLanguage.text(BukkitCommandMessagesExtended.COMMAND_IRIS_STAGED_IRIS_WORLD_WITH_GENERATOR_IRIS_SEED, MessageArgument.untrusted("name", name), MessageArgument.untrusted("value", dimension.getLoadKey()), MessageArgument.untrusted("seed", seed)));
-            if (main) {
-                sender().sendMessage(IrisLanguage.text(BukkitCommandMessagesExtended.COMMAND_IRIS_THIS_WORLD_IS_NOW_CONFIGURED_AS_MAIN_NEXT_RESTART));
-            }
             return true;
         } catch (LifecycleOperationCoordinator.BusyException e) {
             sender().sendMessage(C.YELLOW + e.getMessage());
             return false;
+        } catch (Throwable e) {
+            sender().sendMessage(C.RED + "Failed to stage the complete Iris world: " + e.getMessage());
+            Iris.reportError("Failed to stage complete Folia world \"" + worldKey + "\".", e);
+            return false;
         } finally {
+            if (stagedWorld != null) {
+                deleteDirectorySafely(stagedWorld.toFile());
+            }
             if (worldLease != null) {
                 worldLease.close();
             }
         }
     }
 
-    private boolean registerWorldInBukkitYml(String worldName, String dimension, Long seed) {
-        String logicalWorldName = IrisWorldStorage.logicalName(IrisWorldStorage.keyFromName(worldName));
+    private boolean registerWorldInBukkitYml(NamespacedKey worldKey, String dimension, Long seed) {
+        String configuredWorldName = IrisWorldStorage.configuredWorldName(
+                worldKey,
+                IrisWorldStorage.levelRoot().getName()
+        );
         try {
-            BukkitWorldConfiguration.register(BUKKIT_YML, logicalWorldName, dimension, seed);
-            Iris.info("Registered \"" + logicalWorldName + "\" in bukkit.yml");
+            BukkitWorldConfiguration.register(BUKKIT_YML, configuredWorldName, dimension, seed);
+            Iris.info("Registered \"" + configuredWorldName + "\" in bukkit.yml");
             return true;
         } catch (IOException e) {
             sender().sendMessage(IrisLanguage.text(BukkitCommandMessagesExtended.COMMAND_IRIS_FAILED_UPDATE_BUKKIT_YML, MessageArgument.untrusted("value", String.valueOf(e.getMessage()))));
@@ -1097,31 +923,4 @@ public class CommandIris implements DirectorExecutor {
         }
     }
 
-    static final class MainWorldPublication implements AutoCloseable {
-        private final Path target;
-        private boolean committed;
-        private boolean closed;
-
-        MainWorldPublication(Path target) {
-            this.target = target;
-        }
-
-        void commit() {
-            if (closed) {
-                throw new IllegalStateException("Main-world publication is already closed.");
-            }
-            committed = true;
-        }
-
-        @Override
-        public void close() throws IOException {
-            if (closed) {
-                return;
-            }
-            closed = true;
-            if (!committed) {
-                AtomicDirectoryPublisher.deleteTree(target);
-            }
-        }
-    }
 }

adapters/bukkit/plugin/src/test/java/art/arcane/iris/core/BukkitWorldReconcilerTest.java

@@ -378,6 +378,16 @@ public class BukkitWorldReconcilerTest {
             return configuredSeed;
         }
 
+        @Override
+        public String configuredWorldName(NamespacedKey requestedWorldKey) {
+            return requestedWorldKey.getKey();
+        }
+
+        @Override
+        public NamespacedKey worldKeyFromConfiguration(String configuredWorldName) {
+            return worldKey;
+        }
+
         @Override
         public Optional<World> loadedWorld(NamespacedKey requestedWorldKey) {
             return worldKey.equals(requestedWorldKey) ? loaded : Optional.empty();

adapters/bukkit/plugin/src/test/java/art/arcane/iris/core/IrisWorldGeneratorResolverTest.java

@@ -7,6 +7,7 @@ import org.junit.After;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
+import org.bukkit.NamespacedKey;
 
 import java.io.File;
 import java.nio.charset.StandardCharsets;
@@ -63,6 +64,18 @@ public class IrisWorldGeneratorResolverTest {
         assertFalse(invalid.getBlockingErrors().toString(), invalid.isLoadable());
     }
 
+    @Test
+    public void paperStartupAliasResolvesToCanonicalRuntimeKey() {
+        assertEquals(
+                new NamespacedKey("iris", "moon"),
+                IrisWorldGeneratorResolver.configuredWorldKey("world_iris_moon", "world")
+        );
+        assertEquals(
+                new NamespacedKey("iris", "moon"),
+                IrisWorldGeneratorResolver.configuredWorldKey("moon", "world")
+        );
+    }
+
     private static void writeValidPack(Path packRoot) throws Exception {
         Files.createDirectories(packRoot.resolve("dimensions"));
         Files.createDirectories(packRoot.resolve("regions"));

adapters/bukkit/plugin/src/test/java/art/arcane/iris/core/PendingWorldReplacementManagerPolicyTest.java

@@ -0,0 +1,126 @@
+package art.arcane.iris.core;
+
+import art.arcane.iris.Iris;
+import art.arcane.iris.core.ExactWorldSlotPathPolicy.SlotKind;
+import art.arcane.iris.core.lifecycle.WorldReplacementBootstrapMarker;
+import art.arcane.iris.engine.object.IrisDimension;
+import art.arcane.iris.engine.object.IrisEnvironment;
+import art.arcane.iris.util.common.plugin.VolmitSender;
+import org.bukkit.NamespacedKey;
+import org.junit.After;
+import org.junit.Test;
+import org.mockito.MockedStatic;
+
+import java.io.IOException;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThrows;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.mockStatic;
+
+public class PendingWorldReplacementManagerPolicyTest {
+    @After
+    public void disableValidation() {
+        IrisStartupValidation.disable();
+    }
+
+    @Test
+    public void irisManagedSlotsAllowEveryReplacementEnvironment() {
+        for (IrisEnvironment environment : IrisEnvironment.values()) {
+            PendingWorldReplacementManager.requireCompatibleEnvironment(SlotKind.IRIS_MANAGED, environment);
+        }
+    }
+
+    @Test
+    public void vanillaSlotsRequireTheirIdentityEnvironment() {
+        List<EnvironmentExpectation> expectations = List.of(
+                new EnvironmentExpectation(SlotKind.VANILLA_OVERWORLD, IrisEnvironment.NORMAL),
+                new EnvironmentExpectation(SlotKind.VANILLA_NETHER, IrisEnvironment.NETHER),
+                new EnvironmentExpectation(SlotKind.VANILLA_END, IrisEnvironment.THE_END)
+        );
+
+        for (EnvironmentExpectation expectation : expectations) {
+            for (IrisEnvironment environment : IrisEnvironment.values()) {
+                if (environment == expectation.environment()) {
+                    PendingWorldReplacementManager.requireCompatibleEnvironment(
+                            expectation.slotKind(),
+                            environment
+                    );
+                    continue;
+                }
+                assertThrows(
+                        IllegalArgumentException.class,
+                        () -> PendingWorldReplacementManager.requireCompatibleEnvironment(
+                                expectation.slotKind(),
+                                environment
+                        )
+                );
+            }
+        }
+    }
+
+    @Test
+    public void disabledVanillaSlotsFailWithoutRestrictingOtherSlots() throws Exception {
+        PendingWorldReplacementManager.requireVanillaSlotEnabled(SlotKind.IRIS_MANAGED, false, false);
+        PendingWorldReplacementManager.requireVanillaSlotEnabled(SlotKind.VANILLA_OVERWORLD, false, false);
+        PendingWorldReplacementManager.requireVanillaSlotEnabled(SlotKind.VANILLA_NETHER, true, false);
+        PendingWorldReplacementManager.requireVanillaSlotEnabled(SlotKind.VANILLA_END, false, true);
+
+        IOException netherFailure = assertThrows(
+                IOException.class,
+                () -> PendingWorldReplacementManager.requireVanillaSlotEnabled(
+                        SlotKind.VANILLA_NETHER,
+                        false,
+                        true
+                )
+        );
+        IOException endFailure = assertThrows(
+                IOException.class,
+                () -> PendingWorldReplacementManager.requireVanillaSlotEnabled(
+                        SlotKind.VANILLA_END,
+                        true,
+                        false
+                )
+        );
+
+        assertEquals(
+                "allow-nether must be true before the vanilla Nether can be replaced.",
+                netherFailure.getMessage()
+        );
+        assertEquals(
+                "Bukkit allow-end must be true before the vanilla End can be replaced.",
+                endFailure.getMessage()
+        );
+    }
+
+    @Test
+    public void replacementStagingPassesTheRestartBoundaryWithoutUnlockingCreation() {
+        IrisStartupValidation.begin();
+        IrisStartupValidation.markDatapacksReady();
+        IrisStartupValidation.markPacksReady();
+        IrisStartupValidation.requireRestart("restart boundary");
+        PendingWorldReplacementManager manager = new PendingWorldReplacementManager(mock(Iris.class));
+        VolmitSender sender = mock(VolmitSender.class);
+        IrisDimension dimension = mock(IrisDimension.class);
+
+        assertThrows(IllegalStateException.class, IrisStartupValidation::requireWorldCreationReady);
+        try (MockedStatic<WorldReplacementBootstrapMarker> bootstrapMarker =
+                     mockStatic(WorldReplacementBootstrapMarker.class)) {
+            bootstrapMarker.when(WorldReplacementBootstrapMarker::wasBootstrappedThisProcess).thenReturn(false);
+
+            IOException failure = assertThrows(
+                    IOException.class,
+                    () -> manager.stageReplacement(sender, NamespacedKey.minecraft("the_nether"), dimension)
+            );
+
+            assertEquals(
+                    "Exact world replacement requires a full Paper-family startup bootstrap.",
+                    failure.getMessage()
+            );
+        }
+    }
+
+    private record EnvironmentExpectation(SlotKind slotKind, IrisEnvironment environment) {
+    }
+}

adapters/bukkit/plugin/src/test/java/art/arcane/iris/core/commands/CommandIrisCreateOverwriteContractTest.java

@@ -1,5 +1,6 @@
 package art.arcane.iris.core.commands;
 
+import art.arcane.volmlib.util.director.annotations.Director;
 import art.arcane.volmlib.util.director.annotations.Param;
 import org.junit.Test;
 
@@ -8,28 +9,42 @@ import java.lang.reflect.Parameter;
 import java.util.Arrays;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 public class CommandIrisCreateOverwriteContractTest {
     @Test
-    public void createExposesOptInRestartReplacementFlag() throws Exception {
+    public void createOnlyAcceptsNameTypeAndSeed() throws Exception {
         Method command = CommandIris.class.getDeclaredMethod(
                 "create",
                 String.class,
                 String.class,
-                long.class,
-                boolean.class,
-                boolean.class
+                long.class
         );
-        Parameter overwriteParameter = command.getParameters()[4];
-        Param overwrite = overwriteParameter.getAnnotation(Param.class);
 
-        assertEquals("overwrite", overwrite.name());
-        assertEquals("false", overwrite.defaultValue());
-        assertTrue(Arrays.asList(overwrite.aliases()).contains("force"));
+        assertEquals(3, command.getParameterCount());
+        assertFalse(Arrays.stream(command.getParameterTypes()).anyMatch(type -> type == boolean.class));
+    }
+
+    @Test
+    public void replaceOwnsOverrideAndOverwriteAliasesWithoutASeed() throws Exception {
+        Method command = CommandIris.class.getDeclaredMethod("replace", String.class, String.class);
+        Director director = command.getAnnotation(Director.class);
+        Parameter targetParameter = command.getParameters()[0];
+        Param target = targetParameter.getAnnotation(Param.class);
+        Parameter typeParameter = command.getParameters()[1];
+        Param type = typeParameter.getAnnotation(Param.class);
+
+        assertTrue(Arrays.asList(director.aliases()).contains("override"));
+        assertTrue(Arrays.asList(director.aliases()).contains("overwrite"));
         assertEquals(
                 "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart",
-                overwrite.descriptionKey()
+                director.descriptionKey()
         );
+        assertEquals("target", target.name());
+        assertEquals(director.descriptionKey(), target.descriptionKey());
+        assertEquals("default", type.defaultValue());
+        assertEquals(CommandIris.PackDimensionTypeHandler.class, type.customHandler());
+        assertFalse(Arrays.stream(command.getParameterTypes()).anyMatch(parameterType -> parameterType == long.class));
     }
 }

adapters/bukkit/plugin/src/test/java/art/arcane/iris/core/commands/CommandIrisFoliaCreateContractTest.java

@@ -0,0 +1,48 @@
+package art.arcane.iris.core.commands;
+
+import org.junit.Test;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import static org.junit.Assert.assertTrue;
+
+public class CommandIrisFoliaCreateContractTest {
+    @Test
+    public void ordinaryFoliaCreateRestartsOnlyAfterSuccessfulStagingAndFeedback() throws Exception {
+        String source = Files.readString(Path.of(System.getProperty("iris.commandIrisSource")));
+        String foliaCreate = source.substring(
+                source.indexOf("if (J.isFolia()) {"),
+                source.indexOf("        try {", source.indexOf("if (J.isFolia()) {"))
+        );
+
+        int stage = foliaCreate.indexOf("stageFoliaWorldCreation(worldName, dimension, seed)");
+        int failureExit = foliaCreate.indexOf("if (!staged)");
+        int feedback = foliaCreate.indexOf("COMMAND_IRIS_WORLD_STAGING_COMPLETED_RESTARTING_SERVER_GENERATE_LOAD");
+        int restart = foliaCreate.indexOf("ServerConfigurator.restart(\"Iris staged Folia world");
+
+        assertTrue(stage >= 0);
+        assertTrue(stage < failureExit);
+        assertTrue(failureExit < feedback);
+        assertTrue(feedback < restart);
+    }
+
+    @Test
+    public void foliaStagePublishesCurrentPaperDataBeforeRegisteringStartupAlias() throws Exception {
+        String source = Files.readString(Path.of(System.getProperty("iris.commandIrisSource")));
+        int methodStart = source.indexOf("private boolean stageFoliaWorldCreation(");
+        int methodEnd = source.indexOf("private boolean registerWorldInBukkitYml(", methodStart);
+        String staging = source.substring(methodStart, methodEnd);
+
+        int currentPaperData = staging.indexOf("INMS.get().writeCurrentPaperWorldData(");
+        int pack = staging.indexOf("installIntoWorld(");
+        int publication = staging.indexOf("AtomicDirectoryPublisher.publishAbsent(");
+        int registration = staging.indexOf("registerWorldInBukkitYml(worldKey");
+
+        assertTrue(currentPaperData >= 0);
+        assertTrue(currentPaperData < pack);
+        assertTrue(pack < publication);
+        assertTrue(publication < registration);
+        assertTrue(source.contains("IrisWorldStorage.configuredWorldName("));
+    }
+}

adapters/bukkit/plugin/src/test/java/art/arcane/iris/core/commands/CommandIrisMainWorldPromotionTest.java

@@ -1,93 +0,0 @@
-package art.arcane.iris.core.commands;
-
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.rules.TemporaryFolder;
-
-import java.io.IOException;
-import java.nio.file.FileAlreadyExistsException;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.util.stream.Stream;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertThrows;
-import static org.junit.Assert.assertTrue;
-
-public class CommandIrisMainWorldPromotionTest {
-    @Rule
-    public TemporaryFolder temporaryFolder = new TemporaryFolder();
-
-    @Test
-    public void existingTopLevelWorldIsRefusedWithoutMerging() throws IOException {
-        PromotionPaths paths = createPromotionPaths("existing-target");
-        Files.createDirectories(paths.target());
-        Files.writeString(paths.target().resolve("sentinel.txt"), "keep");
-
-        assertThrows(FileAlreadyExistsException.class, () -> CommandIris.publishMainWorldFiles(
-                paths.current(),
-                paths.sourceDimension(),
-                paths.target()
-        ));
-
-        assertEquals("keep", Files.readString(paths.target().resolve("sentinel.txt")));
-        assertFalse(Files.exists(paths.target().resolve("dimensions/minecraft/overworld/region/r.0.0.mca")));
-        assertFalse(hasPromotionStage(paths.root(), paths.target().getFileName().toString()));
-    }
-
-    @Test
-    public void uncommittedPromotionRollsBackThePublishedWorld() throws IOException {
-        PromotionPaths paths = createPromotionPaths("rollback-target");
-
-        try (CommandIris.MainWorldPublication publication = CommandIris.publishMainWorldFiles(
-                paths.current(),
-                paths.sourceDimension(),
-                paths.target()
-        )) {
-            assertTrue(Files.isRegularFile(paths.target().resolve("data/map.dat")));
-            assertTrue(Files.isRegularFile(paths.target().resolve("dimensions/minecraft/overworld/region/r.0.0.mca")));
-        }
-
-        assertFalse(Files.exists(paths.target()));
-        assertFalse(hasPromotionStage(paths.root(), paths.target().getFileName().toString()));
-    }
-
-    @Test
-    public void committedPromotionKeepsTheCompleteStagedWorld() throws IOException {
-        PromotionPaths paths = createPromotionPaths("committed-target");
-
-        try (CommandIris.MainWorldPublication publication = CommandIris.publishMainWorldFiles(
-                paths.current(),
-                paths.sourceDimension(),
-                paths.target()
-        )) {
-            publication.commit();
-        }
-
-        assertEquals("map", Files.readString(paths.target().resolve("data/map.dat")));
-        assertEquals("region", Files.readString(paths.target().resolve("dimensions/minecraft/overworld/region/r.0.0.mca")));
-        assertFalse(hasPromotionStage(paths.root(), paths.target().getFileName().toString()));
-    }
-
-    private PromotionPaths createPromotionPaths(String targetName) throws IOException {
-        Path root = temporaryFolder.newFolder(targetName + "-root").toPath();
-        Path current = root.resolve("world");
-        Path sourceDimension = current.resolve("dimensions/iris/" + targetName);
-        Path target = root.resolve(targetName);
-        Files.createDirectories(current.resolve("data"));
-        Files.writeString(current.resolve("data/map.dat"), "map");
-        Files.createDirectories(sourceDimension.resolve("region"));
-        Files.writeString(sourceDimension.resolve("region/r.0.0.mca"), "region");
-        return new PromotionPaths(root, current, sourceDimension, target);
-    }
-
-    private boolean hasPromotionStage(Path root, String targetName) throws IOException {
-        try (Stream<Path> entries = Files.list(root)) {
-            return entries.anyMatch(path -> path.getFileName().toString().startsWith("." + targetName + ".promoting-"));
-        }
-    }
-
-    private record PromotionPaths(Path root, Path current, Path sourceDimension, Path target) {
-    }
-}

build.gradle

@@ -123,6 +123,8 @@ nmsBindings.each { key, value ->
         tasks.withType(org.gradle.api.tasks.testing.Test).configureEach {
             systemProperty('iris.nmsChunkGeneratorSource',
                 rootProject.file("adapters/bukkit/nms/${key}/src/main/java/art/arcane/iris/core/nms/${key}/IrisChunkGenerator.java").absolutePath)
+            systemProperty('iris.nmsBindingSource',
+                rootProject.file("adapters/bukkit/nms/${key}/src/main/java/art/arcane/iris/core/nms/${key}/NMSBinding.java").absolutePath)
             systemProperty('iris.nativeStructurePostProcessorSource',
                 rootProject.file('adapters/minecraft-common/src/main/java/art/arcane/iris/nativegen/NativeStructurePostProcessor.java').absolutePath)
             systemProperty('iris.nativeStructureStartInjectorSource',

core/src/main/java/art/arcane/iris/core/IrisDatapackCompiler.java

@@ -1,6 +1,7 @@
 package art.arcane.iris.core;
 
 import art.arcane.iris.BuildConstants;
+import art.arcane.iris.core.lifecycle.BukkitWorldConfiguration.IrisGeneratorBinding;
 import art.arcane.iris.core.loader.IrisData;
 import art.arcane.iris.core.loader.ResourceLoader;
 import art.arcane.iris.core.nms.datapack.DataVersion;
@@ -21,6 +22,7 @@ import java.nio.file.Files;
 import java.nio.file.LinkOption;
 import java.nio.file.Path;
 import java.nio.file.SimpleFileVisitor;
+import java.nio.file.StandardOpenOption;
 import java.nio.file.attribute.BasicFileAttributes;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
@@ -37,9 +39,29 @@ import java.util.concurrent.atomic.AtomicIntegerArray;
 import java.util.stream.Stream;
 
 public final class IrisDatapackCompiler {
-    private static final int INPUT_FINGERPRINT_SCHEMA = 1;
+    private static final int INPUT_FINGERPRINT_SCHEMA = 2;
     private static final int WORLD_PACK_SCAN_DEPTH = 8;
     private static final List<String> INPUT_DIRECTORIES = List.of("dimensions", "biomes", "snippet");
+    private static final String FLAT_VOID_LEVEL_STEM = """
+            {
+              "type": "%s",
+              "generator": {
+                "type": "minecraft:flat",
+                "settings": {
+                  "biome": "minecraft:the_void",
+                  "features": false,
+                  "lakes": false,
+                  "layers": [
+                    {
+                      "block": "minecraft:air",
+                      "height": 1
+                    }
+                  ],
+                  "structure_overrides": []
+                }
+              }
+            }
+            """;
 
     private IrisDatapackCompiler() {
     }
@@ -65,28 +87,37 @@ public final class IrisDatapackCompiler {
 
     public static String computeInputFingerprint(
             List<File> packRoots,
+            List<IrisGeneratorBinding> bindings,
             IDataFixer fixer,
             boolean adjustVanillaHeight
     ) throws IOException {
         Objects.requireNonNull(fixer, "fixer");
         return computeInputFingerprint(
                 packRoots,
+                bindings,
                 adjustVanillaHeight,
                 compilerIdentity(fixer));
     }
 
     static String computeInputFingerprint(
             List<File> packRoots,
+            List<IrisGeneratorBinding> bindings,
             boolean adjustVanillaHeight,
             String compilerIdentity
     ) throws IOException {
         Objects.requireNonNull(packRoots, "packRoots");
         Objects.requireNonNull(compilerIdentity, "compilerIdentity");
+        List<IrisGeneratorBinding> normalizedBindings = normalizeBindings(bindings);
         MessageDigest digest = sha256();
         updateDigestString(digest, "iris-datapack-compiler-input");
         updateDigestInt(digest, INPUT_FINGERPRINT_SCHEMA);
         updateDigestString(digest, compilerIdentity);
         digest.update((byte) (adjustVanillaHeight ? 1 : 0));
+        updateDigestInt(digest, normalizedBindings.size());
+        for (IrisGeneratorBinding binding : normalizedBindings) {
+            updateDigestString(digest, binding.worldKey().toString());
+            updateDigestString(digest, binding.dimension());
+        }
         updateDigestInt(digest, packRoots.size());
 
         for (int index = 0; index < packRoots.size(); index++) {
@@ -139,12 +170,14 @@ public final class IrisDatapackCompiler {
     public static CompilationResult compile(
             List<File> packRoots,
             KList<File> datapackRoots,
+            List<IrisGeneratorBinding> bindings,
             IDataFixer fixer,
             boolean adjustVanillaHeight
     ) throws IOException {
         Objects.requireNonNull(packRoots, "packRoots");
         Objects.requireNonNull(datapackRoots, "datapackRoots");
         Objects.requireNonNull(fixer, "fixer");
+        List<IrisGeneratorBinding> normalizedBindings = normalizeBindings(bindings);
         if (datapackRoots.isEmpty()) {
             throw new IOException("No Iris datapack output roots were provided");
         }
@@ -154,6 +187,7 @@ public final class IrisDatapackCompiler {
 
         DimensionHeight height = new DimensionHeight(fixer);
         Map<String, KSet<String>> biomes = new LinkedHashMap<>();
+        Map<String, List<DimensionCandidate>> dimensions = new LinkedHashMap<>();
         int packCount = 0;
         int dimensionCount = 0;
         for (File packRoot : packRoots) {
@@ -177,6 +211,12 @@ public final class IrisDatapackCompiler {
                     }
                     IrisLogging.debug("  Compiling Dimension " + dimension.getLoadFile().getPath());
                     height.merge(dimension);
+                    dimensions.computeIfAbsent(dimension.getLoadKey(), ignored -> new ArrayList<>())
+                            .add(new DimensionCandidate(
+                                    dimension,
+                                    packRoot.toPath().toAbsolutePath().normalize(),
+                                    dimension.getDimensionType().toJson(fixer)
+                            ));
                     KSet<String> seenBiomes = biomes.computeIfAbsent(dimension.getLoadKey(), ignored -> new KSet<>());
                     dimension.installBiomes(fixer, dimension::getLoader, datapackRoots, seenBiomes);
                     dimension.installDimensionType(fixer, datapackRoots);
@@ -192,10 +232,80 @@ public final class IrisDatapackCompiler {
         }
 
         IrisDimension.writeShared(datapackRoots, height, adjustVanillaHeight);
-        validateOutputs(datapackRoots, dimensionCount);
+        installLevelStemBindings(normalizedBindings, dimensions, datapackRoots);
+        validateOutputs(datapackRoots, dimensionCount, normalizedBindings.size());
         return new CompilationResult(packCount, dimensionCount, countBiomes(biomes));
     }
 
+    private static void installLevelStemBindings(
+            List<IrisGeneratorBinding> bindings,
+            Map<String, List<DimensionCandidate>> dimensions,
+            Collection<File> datapackRoots
+    ) throws IOException {
+        for (IrisGeneratorBinding binding : bindings) {
+            DimensionCandidate selected = resolveDimension(binding, dimensions.get(binding.dimension()));
+            String typeKey = "iris:" + selected.dimension().getDimensionTypeKey();
+            String levelStem = FLAT_VOID_LEVEL_STEM.formatted(typeKey);
+            for (File datapackRoot : datapackRoots) {
+                Path output = datapackRoot.toPath()
+                        .toAbsolutePath()
+                        .normalize()
+                        .resolve("data/iris/dimension")
+                        .resolve(binding.worldKey().key() + ".json");
+                Files.createDirectories(output.getParent());
+                Files.writeString(
+                        output,
+                        levelStem,
+                        StandardCharsets.UTF_8,
+                        StandardOpenOption.CREATE_NEW,
+                        StandardOpenOption.WRITE
+                );
+            }
+        }
+    }
+
+    private static DimensionCandidate resolveDimension(
+            IrisGeneratorBinding binding,
+            List<DimensionCandidate> candidates
+    ) throws IOException {
+        if (candidates == null || candidates.isEmpty()) {
+            throw new IOException("Iris world " + binding.worldKey() + " selects missing dimension \""
+                    + binding.dimension() + "\".");
+        }
+        DimensionCandidate selected = candidates.getFirst();
+        for (int index = 1; index < candidates.size(); index++) {
+            DimensionCandidate candidate = candidates.get(index);
+            if (!selected.dimensionTypeJson().equals(candidate.dimensionTypeJson())) {
+                throw new IOException("Iris world " + binding.worldKey() + " selects ambiguous dimension \""
+                        + binding.dimension() + "\" from " + selected.packRoot() + " and "
+                        + candidate.packRoot() + ".");
+            }
+        }
+        return selected;
+    }
+
+    private static List<IrisGeneratorBinding> normalizeBindings(List<IrisGeneratorBinding> bindings)
+            throws IOException {
+        List<IrisGeneratorBinding> requiredBindings = List.copyOf(
+                Objects.requireNonNull(bindings, "bindings")
+        );
+        Map<WorldSlotKey, IrisGeneratorBinding> byWorld = new LinkedHashMap<>();
+        for (IrisGeneratorBinding binding : requiredBindings) {
+            IrisGeneratorBinding requiredBinding = Objects.requireNonNull(binding, "binding");
+            IrisGeneratorBinding previous = byWorld.putIfAbsent(
+                    requiredBinding.worldKey(),
+                    requiredBinding
+            );
+            if (previous != null) {
+                throw new IOException("Multiple Iris LevelStem bindings target "
+                        + requiredBinding.worldKey() + ".");
+            }
+        }
+        ArrayList<IrisGeneratorBinding> normalized = new ArrayList<>(byWorld.values());
+        normalized.sort(Comparator.comparing(binding -> binding.worldKey().toString()));
+        return List.copyOf(normalized);
+    }
+
     private static void collectInstalledPackRoots(
             Path packsRoot,
             Map<Path, File> roots,
@@ -363,7 +473,11 @@ public final class IrisDatapackCompiler {
         }
     }
 
-    private static void validateOutputs(Collection<File> datapackRoots, int dimensionCount) throws IOException {
+    private static void validateOutputs(
+            Collection<File> datapackRoots,
+            int dimensionCount,
+            int levelStemCount
+    ) throws IOException {
         for (File datapackRoot : datapackRoots) {
             Path root = datapackRoot.toPath();
             if (!Files.isRegularFile(root.resolve("pack.mcmeta"))) {
@@ -372,6 +486,9 @@ public final class IrisDatapackCompiler {
             if (dimensionCount > 0 && !Files.isDirectory(root.resolve("data/iris/dimension_type"))) {
                 throw new IOException("Iris dimension types were not generated at " + root);
             }
+            if (levelStemCount > 0 && !Files.isDirectory(root.resolve("data/iris/dimension"))) {
+                throw new IOException("Iris LevelStem bindings were not generated at " + root);
+            }
         }
     }
 
@@ -389,6 +506,13 @@ public final class IrisDatapackCompiler {
     private record CompilerInputEntry(Path source, String relativePath) {
     }
 
+    private record DimensionCandidate(
+            IrisDimension dimension,
+            Path packRoot,
+            String dimensionTypeJson
+    ) {
+    }
+
     public static final class DimensionHeight {
         private final IDataFixer fixer;
         private final AtomicIntegerArray[] dimensions = new AtomicIntegerArray[3];

core/src/main/java/art/arcane/iris/core/IrisStartupValidation.java

@@ -109,6 +109,16 @@ public final class IrisStartupValidation {
         }
     }
 
+    public static void requireWorldReplacementStagingReady() {
+        Snapshot current = snapshot;
+        if (current.enforced()
+                && current.datapacks() == ValidationState.RESTART_REQUIRED
+                && current.packs() == ValidationState.READY) {
+            return;
+        }
+        requireWorldCreationReady();
+    }
+
     static Snapshot snapshot() {
         return snapshot;
     }

core/src/main/java/art/arcane/iris/core/IrisWorldStorage.java

@@ -10,8 +10,9 @@ import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
-import java.nio.file.Path;
 import java.nio.file.Files;
+import java.nio.file.LinkOption;
+import java.nio.file.Path;
 import java.util.Locale;
 import java.util.Objects;
 import java.util.Optional;
@@ -125,6 +126,54 @@ public final class IrisWorldStorage {
         return key;
     }
 
+    public static NamespacedKey replacementKeyFromName(String requestedName, String levelName) {
+        String requested = Objects.requireNonNull(requestedName, "requestedName").trim();
+        String configuredLevelName = Objects.requireNonNull(levelName, "levelName").trim();
+        if (requested.isEmpty()) {
+            throw new IllegalArgumentException("World name cannot be empty.");
+        }
+        if (configuredLevelName.isEmpty()) {
+            throw new IllegalArgumentException("Configured level name cannot be empty.");
+        }
+        if (requested.contains("/") || requested.contains("\\") || requested.contains("..")) {
+            throw new IllegalArgumentException("World name must be a safe single path segment.");
+        }
+
+        String normalized = requested.toLowerCase(Locale.ENGLISH);
+        if (normalized.contains(":")) {
+            int separator = normalized.indexOf(':');
+            if (separator == 0
+                    || separator == normalized.length() - 1
+                    || separator != normalized.lastIndexOf(':')) {
+                throw new IllegalArgumentException("World identifier is invalid: " + requestedName);
+            }
+            NamespacedKey explicit = NamespacedKey.fromString(normalized);
+            if (explicit == null) {
+                throw new IllegalArgumentException("World identifier is invalid: " + requestedName);
+            }
+            return explicit;
+        }
+        String configuredIrisPrefix = configuredLevelName + "_" + IRIS_NAMESPACE + "_";
+        if (requested.startsWith(configuredIrisPrefix)) {
+            return keyFromConfiguredWorldName(requested, configuredLevelName);
+        }
+        if (requested.equalsIgnoreCase(configuredLevelName)) {
+            return NamespacedKey.minecraft("overworld");
+        }
+        if (requested.equalsIgnoreCase(configuredLevelName + "_nether")) {
+            return NamespacedKey.minecraft("the_nether");
+        }
+        if (requested.equalsIgnoreCase(configuredLevelName + "_the_end")) {
+            return NamespacedKey.minecraft("the_end");
+        }
+        return switch (normalized) {
+            case "main", "overworld" -> NamespacedKey.minecraft("overworld");
+            case "nether", "the_nether" -> NamespacedKey.minecraft("the_nether");
+            case "end", "the_end" -> NamespacedKey.minecraft("the_end");
+            default -> new NamespacedKey(IRIS_NAMESPACE, normalized.replace(' ', '_'));
+        };
+    }
+
     static NamespacedKey keyFromName(String worldName, String levelName) {
         String name = Objects.requireNonNull(worldName, "worldName").trim();
         String mainLevelName = Objects.requireNonNull(levelName, "levelName").trim();
@@ -145,6 +194,53 @@ public final class IrisWorldStorage {
         return new NamespacedKey(IRIS_NAMESPACE, key);
     }
 
+    public static NamespacedKey keyFromConfiguredWorldName(String configuredWorldName, String levelName) {
+        String name = Objects.requireNonNull(configuredWorldName, "configuredWorldName").trim();
+        String mainLevelName = Objects.requireNonNull(levelName, "levelName").trim();
+        if (name.isEmpty()) {
+            throw new IllegalArgumentException("Configured world name cannot be empty.");
+        }
+        if (mainLevelName.isEmpty()) {
+            throw new IllegalArgumentException("Level name cannot be empty.");
+        }
+
+        String irisPrefix = mainLevelName + "_" + IRIS_NAMESPACE + "_";
+        if (name.startsWith(irisPrefix)) {
+            return managedKeyFromName(IRIS_NAMESPACE + ":" + name.substring(irisPrefix.length()), mainLevelName);
+        }
+        return keyFromName(name, mainLevelName);
+    }
+
+    public static String configuredWorldName(NamespacedKey key, String levelName) {
+        NamespacedKey worldKey = Objects.requireNonNull(key, "key");
+        String mainLevelName = Objects.requireNonNull(levelName, "levelName").trim();
+        if (mainLevelName.isEmpty()) {
+            throw new IllegalArgumentException("Level name cannot be empty.");
+        }
+        if (NamespacedKey.minecraft("overworld").equals(worldKey)) {
+            return mainLevelName;
+        }
+        if (NamespacedKey.minecraft("the_nether").equals(worldKey)) {
+            return mainLevelName + "_nether";
+        }
+        if (NamespacedKey.minecraft("the_end").equals(worldKey)) {
+            return mainLevelName + "_the_end";
+        }
+        if (!IRIS_NAMESPACE.equals(worldKey.getNamespace()) || !worldKey.getKey().matches("[a-z0-9_-]+")) {
+            throw new IllegalArgumentException("Only safe Iris-managed world keys have a Bukkit startup name.");
+        }
+        return mainLevelName + "_" + worldKey.getNamespace() + "_" + worldKey.getKey();
+    }
+
+    public static String configuredWorldName(WorldSlotKey key, String levelName) {
+        WorldSlotKey worldKey = Objects.requireNonNull(key, "key");
+        NamespacedKey namespacedKey = NamespacedKey.fromString(worldKey.toString());
+        if (namespacedKey == null) {
+            throw new IllegalArgumentException("World key is invalid: " + worldKey);
+        }
+        return configuredWorldName(namespacedKey, levelName);
+    }
+
     public static String logicalName(WorldInfo world) {
         return logicalName(WorldIdentity.key(world));
     }
@@ -214,6 +310,15 @@ public final class IrisWorldStorage {
         return target.toFile();
     }
 
+    public static boolean isExistingManagedDimensionRoot(File levelRoot, NamespacedKey key) {
+        try {
+            Path target = requireSafeManagedDimensionRoot(levelRoot, key).toPath();
+            return Files.isDirectory(target, LinkOption.NOFOLLOW_LINKS);
+        } catch (IllegalArgumentException exception) {
+            return false;
+        }
+    }
+
     public static File dimensionRoot(File levelRoot, NamespacedKey key) {
         Path dimensionsRoot = Objects.requireNonNull(levelRoot, "levelRoot")
                 .toPath()

core/src/main/java/art/arcane/iris/core/IrisWorlds.java

@@ -14,6 +14,7 @@ import art.arcane.volmlib.util.io.IO;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.reflect.TypeToken;
+import org.bukkit.NamespacedKey;
 import org.bukkit.configuration.ConfigurationSection;
 import org.bukkit.configuration.file.YamlConfiguration;
 
@@ -25,9 +26,11 @@ import java.nio.channels.FileChannel;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.AtomicMoveNotSupportedException;
 import java.nio.file.Files;
+import java.nio.file.LinkOption;
 import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
 import java.nio.file.StandardOpenOption;
+import java.util.Map;
 import java.util.Objects;
 import java.util.stream.Stream;
 
@@ -35,34 +38,41 @@ public class IrisWorlds {
     private static final AtomicCache<IrisWorlds> cache = new AtomicCache<>();
     private static final Gson GSON = new GsonBuilder().setPrettyPrinting().create();
     private static final Type TYPE = TypeToken.getParameterized(KMap.class, String.class, String.class).getType();
+    private final Path levelRoot;
+    private final Path registryFile;
     private final KMap<String, String> worlds;
     private volatile boolean dirty = false;
 
-    private IrisWorlds(KMap<String, String> worlds) {
+    private IrisWorlds(Path levelRoot, KMap<String, String> worlds) {
+        this.levelRoot = Objects.requireNonNull(levelRoot, "levelRoot").toAbsolutePath().normalize();
+        registryFile = registryFile(this.levelRoot);
         this.worlds = new KMap<>();
         worlds.forEach((identity, type) -> this.worlds.put(WorldIdentity.parse(identity).toString(), type));
-        readBukkitWorlds().forEach((name, type) -> put0(IrisWorldStorage.keyFromName(name).toString(), type));
+        readBukkitWorlds(this.levelRoot).forEach((name, type) -> put0(
+                IrisWorldStorage.keyFromConfiguredWorldName(name, this.levelRoot.getFileName().toString()).toString(),
+                type));
         save();
     }
 
     public static IrisWorlds get() {
         return cache.aquire(() -> {
-            File file = IrisPlatforms.get().dataFile("worlds.json");
+            Path levelRoot = IrisWorldStorage.levelRoot().toPath().toAbsolutePath().normalize();
+            File file = registryFile(levelRoot).toFile();
             if (!file.exists()) {
-                return new IrisWorlds(new KMap<>());
+                return new IrisWorlds(levelRoot, new KMap<>());
             }
 
             try {
                 String json = IO.readAll(file);
                 KMap<String, String> worlds = GSON.fromJson(json, TYPE);
-                return new IrisWorlds(Objects.requireNonNullElseGet(worlds, KMap::new));
+                return new IrisWorlds(levelRoot, Objects.requireNonNullElseGet(worlds, KMap::new));
             } catch (Throwable e) {
-                IrisLogging.error("Failed to load worlds.json!");
+                IrisLogging.error("Failed to load worlds.json for level root " + levelRoot + "!");
                 e.printStackTrace();
                 IrisLogging.reportError(e);
             }
 
-            return new IrisWorlds(new KMap<>());
+            return new IrisWorlds(levelRoot, new KMap<>());
         });
     }
 
@@ -114,7 +124,9 @@ public class IrisWorlds {
     public synchronized KMap<String, String> getWorlds() {
         clean();
         KMap<String, String> result = new KMap<>();
-        readBukkitWorlds().forEach((name, type) -> result.put(IrisWorldStorage.keyFromName(name).toString(), type));
+        readBukkitWorlds(levelRoot).forEach((name, type) -> result.put(
+                IrisWorldStorage.keyFromConfiguredWorldName(name, levelRoot.getFileName().toString()).toString(),
+                type));
         return result.put(worlds);
     }
 
@@ -135,7 +147,7 @@ public class IrisWorlds {
     public synchronized void clean() {
         boolean removed = worlds.entrySet().removeIf(entry -> {
             try {
-                File packRoot = IrisWorldStorage.packRoot(WorldIdentity.parse(entry.getKey()));
+                File packRoot = packRoot(entry.getKey());
                 return !new File(packRoot, "dimensions/" + entry.getValue() + ".json").exists();
             } catch (IllegalArgumentException e) {
                 return true;
@@ -159,7 +171,7 @@ public class IrisWorlds {
             return;
         }
 
-        Path target = IrisPlatforms.get().dataFile("worlds.json").toPath().toAbsolutePath().normalize();
+        Path target = registryFile;
         Path parent = target.getParent();
         if (parent == null) {
             throw new IOException("worlds.json target has no parent: " + target);
@@ -193,6 +205,49 @@ public class IrisWorlds {
     }
 
     public static KMap<String, String> readBukkitWorlds() {
+        return readBukkitWorlds(IrisWorldStorage.levelRoot().toPath());
+    }
+
+    static Path registryFile(Path levelRoot) {
+        return Objects.requireNonNull(levelRoot, "levelRoot")
+                .toAbsolutePath()
+                .normalize()
+                .resolve("iris")
+                .resolve("worlds.json");
+    }
+
+    static KMap<String, String> filterBukkitWorldsByStorage(
+            Path levelRoot,
+            Map<String, String> configuredWorlds
+    ) {
+        Path root = Objects.requireNonNull(levelRoot, "levelRoot").toAbsolutePath().normalize();
+        Path levelNamePath = root.getFileName();
+        if (levelNamePath == null) {
+            throw new IllegalArgumentException("Selected level root has no name: " + root);
+        }
+
+        KMap<String, String> result = new KMap<>();
+        for (Map.Entry<String, String> entry : Objects.requireNonNull(configuredWorlds, "configuredWorlds").entrySet()) {
+            String configuredWorldName = entry.getKey();
+            NamespacedKey worldKey = IrisWorldStorage.keyFromConfiguredWorldName(
+                    configuredWorldName,
+                    levelNamePath.toString());
+            if (!IrisWorldStorage.configuredWorldName(worldKey, levelNamePath.toString())
+                    .equals(configuredWorldName)) {
+                continue;
+            }
+            Path dimensionRoot = IrisWorldStorage.dimensionRoot(root.toFile(), worldKey)
+                    .toPath()
+                    .toAbsolutePath()
+                    .normalize();
+            if (Files.isDirectory(dimensionRoot, LinkOption.NOFOLLOW_LINKS)) {
+                result.put(configuredWorldName, entry.getValue());
+            }
+        }
+        return result;
+    }
+
+    private static KMap<String, String> readBukkitWorlds(Path levelRoot) {
         YamlConfiguration bukkit = YamlConfiguration.loadConfiguration(ServerProperties.BUKKIT_YML);
         ConfigurationSection worlds = bukkit.getConfigurationSection("worlds");
         if (worlds == null) return new KMap<>();
@@ -212,11 +267,16 @@ public class IrisWorlds {
             result.put(world, loadKey);
         }
 
-        return result;
+        return filterBukkitWorldsByStorage(levelRoot, result);
     }
 
-    private static IrisDimension loadDimension(String worldIdentity, String id) {
-        File pack = IrisWorldStorage.packRoot(WorldIdentity.parse(worldIdentity));
+    private File packRoot(String worldIdentity) {
+        NamespacedKey worldKey = WorldIdentity.parse(worldIdentity);
+        return new File(IrisWorldStorage.dimensionRoot(levelRoot.toFile(), worldKey), "iris/pack");
+    }
+
+    private IrisDimension loadDimension(String worldIdentity, String id) {
+        File pack = packRoot(worldIdentity);
         IrisDimension dimension = pack.isDirectory() ? IrisData.get(pack).getDimensionLoader().load(id) : null;
         if (dimension == null) {
             dimension = IrisData.loadAnyDimension(id, null);

core/src/main/java/art/arcane/iris/core/ServerConfigurator.java

@@ -24,6 +24,8 @@ import art.arcane.iris.core.datapack.DatapackIngestService;
 import art.arcane.iris.core.datapack.DatapackIngestService.ReapplyOutcome;
 import art.arcane.iris.core.loader.IrisData;
 import art.arcane.iris.core.loader.ResourceLoader;
+import art.arcane.iris.core.lifecycle.BukkitWorldConfiguration;
+import art.arcane.iris.core.lifecycle.BukkitWorldConfiguration.IrisGeneratorBinding;
 import art.arcane.iris.core.lifecycle.LifecycleOperationCoordinator;
 import art.arcane.iris.core.nms.INMS;
 import art.arcane.iris.core.nms.datapack.DataVersion;
@@ -276,10 +278,12 @@ public class ServerConfigurator {
             IrisLogging.debug("Checking Data Packs...");
         }
         List<File> packRoots;
+        List<IrisGeneratorBinding> bindings;
         try {
             packRoots = collectCompilerPackRoots();
+            bindings = collectConfiguredLevelStemBindings();
         } catch (IOException exception) {
-            IrisLogging.reportError("Unable to resolve Iris datapack compiler roots.", exception);
+            IrisLogging.reportError("Unable to resolve Iris datapack compiler inputs.", exception);
             return DatapackInstallResult.failedResult();
         }
 
@@ -303,6 +307,7 @@ public class ServerConfigurator {
             IrisDatapackCompiler.compile(
                     packRoots,
                     stagedRoots,
+                    bindings,
                     fixer,
                     IrisSettings.get().getGeneral().adjustVanillaHeight
             );
@@ -445,11 +450,25 @@ public class ServerConfigurator {
                 IrisWorldStorage.levelRoot().toPath());
     }
 
+    private static List<IrisGeneratorBinding> collectConfiguredLevelStemBindings() throws IOException {
+        File levelRoot = IrisWorldStorage.levelRoot();
+        String levelId = levelRoot.getName();
+        if (levelId.isBlank()) {
+            throw new IOException("Configured level root has no Paper startup level id: " + levelRoot);
+        }
+        return BukkitWorldConfiguration.readIrisGeneratorBindings(
+                ServerProperties.BUKKIT_YML,
+                levelId,
+                levelRoot.toPath()
+        );
+    }
+
     private static String computeCurrentDatapackCompilerInputFingerprint(IDataFixer fixer) throws IOException {
         return IrisDatapackCompiler.computeInputFingerprint(
                 IrisDatapackCompiler.collectCompilerInputRoots(
                         IrisPlatforms.get().dataFolder().toPath(),
                         IrisWorldStorage.levelRoot().toPath()),
+                collectConfiguredLevelStemBindings(),
                 Objects.requireNonNull(fixer, "Datapack fixer"),
                 IrisSettings.get().getGeneral().adjustVanillaHeight);
     }

core/src/main/java/art/arcane/iris/core/lifecycle/BukkitWorldConfiguration.java

@@ -1,5 +1,8 @@
 package art.arcane.iris.core.lifecycle;
 
+import art.arcane.iris.core.IrisWorldStorage;
+import art.arcane.iris.core.WorldSlotKey;
+import org.bukkit.NamespacedKey;
 import org.bukkit.configuration.ConfigurationSection;
 import org.bukkit.configuration.InvalidConfigurationException;
 import org.bukkit.configuration.file.YamlConfiguration;
@@ -15,6 +18,10 @@ import java.nio.file.StandardCopyOption;
 import java.nio.file.StandardOpenOption;
 import java.nio.file.attribute.BasicFileAttributes;
 import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 import java.util.function.Predicate;
 
@@ -91,6 +98,95 @@ public final class BukkitWorldConfiguration {
         }
     }
 
+    public static List<IrisGeneratorBinding> readIrisGeneratorBindings(
+            File configurationFile,
+            String levelName,
+            Path levelRoot
+    ) throws IOException {
+        File requiredConfigurationFile = Objects.requireNonNull(configurationFile, "configurationFile");
+        String requiredLevelName = requireName(levelName, "Level name");
+        Path requiredLevelRoot = Objects.requireNonNull(levelRoot, "levelRoot")
+                .toAbsolutePath()
+                .normalize();
+        Path configurationPath = requiredConfigurationFile.toPath();
+        if (!Files.exists(configurationPath, LinkOption.NOFOLLOW_LINKS)) {
+            return List.of();
+        }
+        synchronized (MUTATION_LOCK) {
+            YamlConfiguration configuration = load(requiredConfigurationFile);
+            Object rawWorlds = configuration.get("worlds");
+            ConfigurationSection worlds = configuration.getConfigurationSection("worlds");
+            if (rawWorlds != null && worlds == null) {
+                throw new IOException("bukkit.yml worlds entry is not a section.");
+            }
+            if (worlds == null) {
+                return List.of();
+            }
+
+            List<String> configuredNames = new ArrayList<>(worlds.getKeys(false));
+            configuredNames.sort(Comparator.naturalOrder());
+            Map<WorldSlotKey, IrisGeneratorBinding> bindings = new LinkedHashMap<>();
+            for (String configuredName : configuredNames) {
+                Object rawWorld = worlds.get(configuredName);
+                ConfigurationSection world = worlds.getConfigurationSection(configuredName);
+                if (rawWorld != null && world == null) {
+                    throw new IOException("bukkit.yml world entry \"" + configuredName + "\" is not a section.");
+                }
+                if (world == null || !world.getKeys(false).contains("generator")) {
+                    continue;
+                }
+                Object rawGenerator = world.get("generator");
+                if (!(rawGenerator instanceof String generator)) {
+                    throw new IOException("bukkit.yml generator for world \"" + configuredName
+                            + "\" is not a string.");
+                }
+                String configuredGenerator = generator.trim();
+                if (!configuredGenerator.equalsIgnoreCase("Iris")
+                        && !configuredGenerator.regionMatches(true, 0, "Iris:", 0, 5)) {
+                    continue;
+                }
+
+                NamespacedKey namespacedKey;
+                try {
+                    namespacedKey = IrisWorldStorage.keyFromConfiguredWorldName(
+                            configuredName,
+                            requiredLevelName
+                    );
+                } catch (IllegalArgumentException failure) {
+                    throw new IOException("bukkit.yml contains an invalid Iris world name \""
+                            + configuredName + "\".", failure);
+                }
+                if (!"iris".equals(namespacedKey.getNamespace())) {
+                    continue;
+                }
+                if (!configuredName.equals(IrisWorldStorage.configuredWorldName(
+                        namespacedKey,
+                        requiredLevelName
+                ))) {
+                    continue;
+                }
+                if (!IrisWorldStorage.isExistingManagedDimensionRoot(
+                        requiredLevelRoot.toFile(),
+                        namespacedKey
+                )) {
+                    continue;
+                }
+                String dimension = selectedIrisDimension(configuredGenerator, configuredName);
+                WorldSlotKey worldKey = new WorldSlotKey(
+                        namespacedKey.getNamespace(),
+                        namespacedKey.getKey()
+                );
+                IrisGeneratorBinding binding = new IrisGeneratorBinding(configuredName, worldKey, dimension);
+                IrisGeneratorBinding previous = bindings.putIfAbsent(worldKey, binding);
+                if (previous != null) {
+                    throw new IOException("bukkit.yml maps both \"" + previous.configuredWorldName()
+                            + "\" and \"" + configuredName + "\" to " + worldKey + ".");
+                }
+            }
+            return List.copyOf(bindings.values());
+        }
+    }
+
     public static GeneratorReplacement replaceIfMatching(
             File configurationFile,
             String worldName,
@@ -396,11 +492,40 @@ public final class BukkitWorldConfiguration {
         return value.trim();
     }
 
+    private static String selectedIrisDimension(String configuredGenerator, String worldName) throws IOException {
+        if (configuredGenerator.equalsIgnoreCase("Iris")) {
+            throw new IOException("bukkit.yml Iris generator for custom world \"" + worldName
+                    + "\" must select a dimension with Iris:<dimension>.");
+        }
+        String dimension = configuredGenerator.substring(5).trim();
+        if (dimension.isEmpty()) {
+            throw new IOException("bukkit.yml Iris generator for world \"" + worldName
+                    + "\" does not select a dimension.");
+        }
+        return dimension;
+    }
+
     public enum Registration {
         CREATED,
         UNCHANGED
     }
 
+    public record IrisGeneratorBinding(
+            String configuredWorldName,
+            WorldSlotKey worldKey,
+            String dimension
+    ) {
+        public IrisGeneratorBinding {
+            configuredWorldName = requireName(configuredWorldName, "Configured world name");
+            WorldSlotKey requiredWorldKey = Objects.requireNonNull(worldKey, "worldKey");
+            if (!"iris".equals(requiredWorldKey.namespace())
+                    || !requiredWorldKey.key().matches("[a-z0-9_-]+")) {
+                throw new IllegalArgumentException("Only safe Iris-managed keys can have LevelStem bindings.");
+            }
+            dimension = requireName(dimension, "Iris dimension");
+        }
+    }
+
     public record WorldGeneratorSnapshot(
             boolean worldsSectionPresent,
             boolean worldSectionPresent,

core/src/main/java/art/arcane/iris/core/lifecycle/IrisWorldRemovalService.java

@@ -18,6 +18,7 @@ import art.arcane.volmlib.util.bukkit.WorldIdentity;
 import org.bukkit.Bukkit;
 import org.bukkit.Location;
 import org.bukkit.World;
+import org.bukkit.configuration.ConfigurationSection;
 import org.bukkit.configuration.file.YamlConfiguration;
 import org.bukkit.entity.Player;
 
@@ -695,6 +696,28 @@ public final class IrisWorldRemovalService {
         }
     }
 
+    static String bukkitConfigurationWorldName(WorldRemovalPathPolicy.Target target) {
+        WorldRemovalPathPolicy.Target requiredTarget = Objects.requireNonNull(target, "target");
+        Path levelName = requiredTarget.levelRoot().getFileName();
+        if (levelName == null || levelName.toString().isBlank()) {
+            throw new IllegalArgumentException("Level root must have a Bukkit startup name.");
+        }
+        return IrisWorldStorage.configuredWorldName(requiredTarget.worldKey(), levelName.toString());
+    }
+
+    static String bukkitGenerator(
+            YamlConfiguration configuration,
+            WorldRemovalPathPolicy.Target target
+    ) {
+        ConfigurationSection worlds = Objects.requireNonNull(configuration, "configuration")
+                .getConfigurationSection("worlds");
+        if (worlds == null) {
+            return null;
+        }
+        ConfigurationSection world = worlds.getConfigurationSection(bukkitConfigurationWorldName(target));
+        return world == null ? null : world.getString("generator");
+    }
+
     private static final class RemovalFailure extends CompletionException {
         private final RemovalStatus status;
         private final Path quarantineDirectory;
@@ -840,7 +863,7 @@ public final class IrisWorldRemovalService {
                     try {
                         boolean bukkitChanged = BukkitWorldConfiguration.remove(
                                 ServerProperties.BUKKIT_YML,
-                                target.logicalName()
+                                bukkitConfigurationWorldName(target)
                         );
                         return new ConfigurationDisposition(multiverseChanged || bukkitChanged, null);
                     } catch (Throwable failure) {
@@ -931,7 +954,7 @@ public final class IrisWorldRemovalService {
             );
             boolean directoryPresent = Files.isDirectory(target.worldDirectory(), LinkOption.NOFOLLOW_LINKS);
             YamlConfiguration configuration = YamlConfiguration.loadConfiguration(ServerProperties.BUKKIT_YML);
-            String generator = configuration.getString("worlds." + target.logicalName() + ".generator");
+            String generator = bukkitGenerator(configuration, target);
             boolean configurationManaged = generator != null
                     && (generator.equalsIgnoreCase("Iris") || generator.regionMatches(true, 0, "Iris:", 0, 5));
             boolean conflictingConfiguration = generator != null && !configurationManaged;

core/src/main/java/art/arcane/iris/core/lifecycle/LifecycleOperationCoordinator.java

@@ -180,7 +180,6 @@ public final class LifecycleOperationCoordinator {
         WORLD_UNLOAD,
         WORLD_REMOVE,
         WORLD_REPLACE,
-        WORLD_PROMOTE,
         STUDIO_OPEN,
         STUDIO_CLOSE,
         PACK_CREATE,

core/src/main/java/art/arcane/iris/core/lifecycle/WorldReplacementFilesystem.java

@@ -2,6 +2,7 @@ package art.arcane.iris.core.lifecycle;
 
 import art.arcane.iris.core.ExactWorldSlotPathPolicy;
 import art.arcane.iris.core.SnapshotDirectoryTreeDeleter;
+import art.arcane.iris.core.pack.PackDirectoryResolver;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -27,6 +28,7 @@ import java.util.regex.Pattern;
 import java.util.stream.Stream;
 
 public final class WorldReplacementFilesystem {
+    private static final String CODE_WORKSPACE_SUFFIX = ".code-workspace";
     private static final List<Path> PAPER_WORLD_METADATA = List.of(
             Path.of("data/paper/metadata.dat"),
             Path.of("data/paper/level_overrides.dat"),
@@ -55,15 +57,15 @@ public final class WorldReplacementFilesystem {
         ReplacementPaths requiredPaths = Objects.requireNonNull(paths, "paths");
         State state = inspect(requiredPaths);
         if (!state.targetPresent()) {
-            throw new IOException("overwrite=true requires an existing exact world slot; use ordinary create for a new world.");
+            throw new IOException("/iris replace requires an existing exact world slot; use /iris create for a new world.");
         }
         if (state.stagePresent() || state.backupPresent()) {
             throw new IOException("A replacement artifact already exists for this transaction.");
         }
-        requireMigratedRetainedWorld(requiredPaths.target());
+        requireCurrentPaperWorld(requiredPaths.target());
     }
 
-    public static void requireMigratedRetainedWorld(Path retainedWorld) throws IOException {
+    public static void requireCurrentPaperWorld(Path retainedWorld) throws IOException {
         try {
             requireDirectory(retainedWorld, "retained world");
             requireDirectory(retainedWorld.resolve("data"), "retained world data");
@@ -249,13 +251,15 @@ public final class WorldReplacementFilesystem {
         try (Stream<Path> stream = Files.walk(root)) {
             files = stream
                     .filter(path -> !path.equals(root))
-                    .filter(path -> !containsMetadataSegment(root.relativize(path)))
                     .sorted(Comparator.comparing(path -> root.relativize(path).toString()))
                     .toList();
         }
         for (Path file : files) {
             BasicFileAttributes attributes = requireSafeEntry(file);
             Path relative = root.relativize(file);
+            if (isGeneratedPackMetadata(relative, attributes)) {
+                continue;
+            }
             update(digest, relative.toString().replace(file.getFileSystem().getSeparator(), "/"));
             digest.update((byte) (attributes.isDirectory() ? 1 : 0));
             if (!attributes.isRegularFile()) {
@@ -304,13 +308,10 @@ public final class WorldReplacementFilesystem {
         return fingerprint;
     }
 
-    private static boolean containsMetadataSegment(Path relative) {
-        for (Path component : relative) {
-            if (".iris".equals(component.toString())) {
-                return true;
-            }
-        }
-        return false;
+    private static boolean isGeneratedPackMetadata(Path relative, BasicFileAttributes attributes) {
+        return PackDirectoryResolver.isHiddenName(relative.getName(0).toString())
+                || attributes.isRegularFile()
+                && relative.getFileName().toString().endsWith(CODE_WORKSPACE_SUFFIX);
     }
 
     private static BasicFileAttributes requireSafeEntry(Path path) throws IOException {
@@ -347,7 +348,7 @@ public final class WorldReplacementFilesystem {
     }
 
     private static void preservePaperWorldMetadata(Path retainedWorld, Path replacementWorld) throws IOException {
-        requireMigratedRetainedWorld(retainedWorld);
+        requireCurrentPaperWorld(retainedWorld);
         requireDirectory(replacementWorld, "replacement world");
         ensureDirectory(replacementWorld.resolve("data"), "replacement world data");
         ensureDirectory(replacementWorld.resolve("data/paper"), "replacement Paper data");

core/src/main/java/art/arcane/iris/core/lifecycle/WorldReplacementJournal.java

@@ -1,6 +1,7 @@
 package art.arcane.iris.core.lifecycle;
 
 import art.arcane.iris.core.ExactWorldSlotPathPolicy;
+import art.arcane.iris.core.IrisWorldStorage;
 import art.arcane.iris.core.WorldSlotKey;
 import art.arcane.iris.core.lifecycle.BukkitWorldConfiguration.WorldGeneratorSnapshot;
 
@@ -152,15 +153,7 @@ public final class WorldReplacementJournal {
         }
         String levelName = fileName.toString();
         if ("iris".equals(requiredWorldKey.namespace())) {
-            String logicalName = requiredWorldKey.key();
-            if (logicalName.equals(levelName)
-                    || logicalName.equals(levelName + "_nether")
-                    || logicalName.equals(levelName + "_the_end")) {
-                throw new IllegalArgumentException(
-                        "An Iris-managed world cannot use a configured vanilla world alias."
-                );
-            }
-            return logicalName;
+            return IrisWorldStorage.configuredWorldName(requiredWorldKey, levelName);
         }
         if (WorldSlotKey.minecraft("overworld").equals(requiredWorldKey)) {
             return levelName;

core/src/main/java/art/arcane/iris/core/lifecycle/WorldReplacementSeed.java

@@ -0,0 +1,119 @@
+package art.arcane.iris.core.lifecycle;
+
+import art.arcane.volmlib.util.nbt.io.NBTUtil;
+import art.arcane.volmlib.util.nbt.io.NamedTag;
+import art.arcane.volmlib.util.nbt.tag.CompoundTag;
+import art.arcane.volmlib.util.nbt.tag.LongTag;
+import art.arcane.volmlib.util.nbt.tag.Tag;
+
+import java.io.IOException;
+import java.nio.channels.FileChannel;
+import java.nio.file.AtomicMoveNotSupportedException;
+import java.nio.file.Files;
+import java.nio.file.LinkOption;
+import java.nio.file.Path;
+import java.nio.file.StandardCopyOption;
+import java.nio.file.StandardOpenOption;
+import java.nio.file.attribute.BasicFileAttributes;
+import java.util.Objects;
+
+public final class WorldReplacementSeed {
+    private static final Path WORLD_GEN_SETTINGS = Path.of("data/minecraft/world_gen_settings.dat");
+
+    private WorldReplacementSeed() {
+    }
+
+    public static long readAuthoritativeSeed(Path worldDirectory) throws IOException {
+        Path requiredWorldDirectory = Objects.requireNonNull(worldDirectory, "worldDirectory")
+                .toAbsolutePath()
+                .normalize();
+        Path settings = requiredWorldDirectory.resolve(WORLD_GEN_SETTINGS);
+        NamedTag namedTag = readSettings(settings);
+        return requireData(namedTag, settings).getLongTag("seed").asLong();
+    }
+
+    public static void copyWithAuthoritativeSeed(
+            Path sourceWorldDirectory,
+            Path targetWorldDirectory,
+            long seed
+    ) throws IOException {
+        Path sourceWorld = Objects.requireNonNull(sourceWorldDirectory, "sourceWorldDirectory")
+                .toAbsolutePath()
+                .normalize();
+        Path targetWorld = Objects.requireNonNull(targetWorldDirectory, "targetWorldDirectory")
+                .toAbsolutePath()
+                .normalize();
+        Path source = sourceWorld.resolve(WORLD_GEN_SETTINGS);
+        Path target = targetWorld.resolve(WORLD_GEN_SETTINGS);
+        NamedTag namedTag = readSettings(source);
+        CompoundTag data = requireData(namedTag, source);
+        data.putLong("seed", seed);
+
+        if (Files.exists(target, LinkOption.NOFOLLOW_LINKS) || Files.isSymbolicLink(target)) {
+            throw new IOException("Staged Paper world generation settings already exist: " + target);
+        }
+        Path parent = target.getParent();
+        if (parent == null) {
+            throw new IOException("Staged Paper world generation settings have no parent: " + target);
+        }
+        Files.createDirectories(parent);
+        Path staged = Files.createTempFile(parent, ".world-gen-settings-", ".dat");
+        try {
+            NBTUtil.write(namedTag, staged.toFile(), true);
+            try (FileChannel channel = FileChannel.open(staged, StandardOpenOption.WRITE)) {
+                channel.force(true);
+            }
+            try {
+                Files.move(staged, target, StandardCopyOption.ATOMIC_MOVE);
+            } catch (AtomicMoveNotSupportedException exception) {
+                Files.move(staged, target);
+            }
+        } finally {
+            Files.deleteIfExists(staged);
+        }
+
+        long writtenSeed = readAuthoritativeSeed(targetWorld);
+        if (writtenSeed != seed) {
+            throw new IOException("Staged Paper world generation settings did not retain the requested seed.");
+        }
+    }
+
+    private static NamedTag readSettings(Path settings) throws IOException {
+        BasicFileAttributes attributes = Files.readAttributes(
+                settings,
+                BasicFileAttributes.class,
+                LinkOption.NOFOLLOW_LINKS
+        );
+        if (attributes.isSymbolicLink() || !attributes.isRegularFile()) {
+            throw new IOException("Paper world generation settings are not a regular file: " + settings);
+        }
+
+        try {
+            return NBTUtil.read(settings.toFile());
+        } catch (IOException failure) {
+            throw new IOException("Could not read Paper world generation settings: " + settings, failure);
+        }
+    }
+
+    private static CompoundTag requireData(NamedTag namedTag, Path settings) throws IOException {
+        Tag<?> rootTag = namedTag.getTag();
+        if (!(rootTag instanceof CompoundTag root)) {
+            throw new IOException("Paper world generation settings must have a compound root: " + settings);
+        }
+        Tag<?> dataTag = root.get("data");
+        if (dataTag == null) {
+            throw new IOException("Paper world generation settings are missing data: " + settings);
+        }
+        if (!(dataTag instanceof CompoundTag data)) {
+            throw new IOException("Paper world generation settings data must be a compound tag: " + settings);
+        }
+        Tag<?> seedTag = data.get("seed");
+        if (seedTag == null) {
+            throw new IOException("Paper world generation settings are missing data.seed: " + settings);
+        }
+        if (!(seedTag instanceof LongTag seed)) {
+            throw new IOException("Paper world generation settings data.seed must be a long tag: " + settings);
+        }
+        return data;
+    }
+}

core/src/main/java/art/arcane/iris/core/localization/BukkitCommandMessagesExtended.java

@@ -175,9 +175,9 @@ public final class BukkitCommandMessagesExtended {
             "iris.bukkit.commandiris.try_one_overworld_vanilla_flat_theend",
             C.YELLOW + "Try one of: overworld, vanilla, flat, theend"
     );
-    public static final TextKey COMMAND_IRIS_WORLD_STAGING_COMPLETED_RESTART_SERVER_GENERATE_LOAD = TextKey.of(
-            "iris.bukkit.commandiris.world_staging_completed_restart_server_generate_load",
-            C.GREEN + "World staging completed. Restart the server to generate/load \"" + "{worldName}" + "\"."
+    public static final TextKey COMMAND_IRIS_WORLD_STAGING_COMPLETED_RESTARTING_SERVER_GENERATE_LOAD = TextKey.of(
+            "iris.bukkit.commandiris.world_staging_completed_restarting_server_generate_load",
+            C.GREEN + "World staging completed. Iris is restarting the server to generate/load \"" + "{worldName}" + "\"."
     );
     public static final TextKey COMMAND_IRIS_EXCEPTION_RAISED_DURING_CREATION_SEE_CONSOLE_MORE_DETAILS = TextKey.of(
             "iris.bukkit.commandiris.exception_raised_during_creation_see_console_more_details",
@@ -187,10 +187,6 @@ public final class BukkitCommandMessagesExtended {
             "iris.bukkit.commandiris.successfully_created_your_world",
             C.GREEN + "Successfully created your world!"
     );
-    public static final TextKey COMMAND_IRIS_YOUR_WORLD_WILL_AUTOMATICALLY_BE_SET_AS_MAIN_WORLD_WHEN = TextKey.of(
-            "iris.bukkit.commandiris.your_world_will_automatically_be_set_as_main_world_when",
-            C.GREEN + "Your world will automatically be set as the main world when the server restarts."
-    );
     public static final TextKey COMMAND_IRIS_RUNTIME_WORLD_CREATION_IS_DISABLED_ON_FOLIA = TextKey.of(
             "iris.bukkit.commandiris.runtime_world_creation_is_disabled_on_folia",
             C.YELLOW + "Runtime world creation is disabled on Folia."
@@ -203,22 +199,10 @@ public final class BukkitCommandMessagesExtended {
             "iris.bukkit.commandiris.failed_stage_world_files_dimension",
             C.RED + "Failed to stage world files for dimension \"" + "{value}" + "\"."
     );
-    public static final TextKey COMMAND_IRIS_UPDATED_SERVER_PROPERTIES_LEVEL_NAME = TextKey.of(
-            "iris.bukkit.commandiris.updated_server_properties_level_name",
-            C.GREEN + "Updated server.properties level-name to \"" + "{name}" + "\"."
-    );
-    public static final TextKey COMMAND_IRIS_WORLD_WAS_STAGED_BUT_FAILED_UPDATE_SERVER_PROPERTIES_MAIN_WORLD = TextKey.of(
-            "iris.bukkit.commandiris.world_was_staged_but_failed_update_server_properties_main_world",
-            C.RED + "World was staged, but failed to update server.properties main world."
-    );
     public static final TextKey COMMAND_IRIS_STAGED_IRIS_WORLD_WITH_GENERATOR_IRIS_SEED = TextKey.of(
             "iris.bukkit.commandiris.staged_iris_world_with_generator_iris_seed",
             C.GREEN + "Staged Iris world \"" + "{name}" + "\" with generator Iris:" + "{value}" + " and seed " + "{seed}" + "."
     );
-    public static final TextKey COMMAND_IRIS_THIS_WORLD_IS_NOW_CONFIGURED_AS_MAIN_NEXT_RESTART = TextKey.of(
-            "iris.bukkit.commandiris.this_world_is_now_configured_as_main_next_restart",
-            C.GREEN + "This world is now configured as main for next restart."
-    );
     public static final TextKey COMMAND_IRIS_FAILED_UPDATE_BUKKIT_YML = TextKey.of(
             "iris.bukkit.commandiris.failed_update_bukkit_yml",
             C.RED + "Failed to update bukkit.yml: " + "{value}"
@@ -878,17 +862,13 @@ public final class BukkitCommandMessagesExtended {
             COMMAND_IRIS_MAY_WE_SUGGEST_NAME_IRISWORLD_INSTEAD_2,
             COMMAND_IRIS_THAT_FOLDER_ALREADY_EXISTS,
             COMMAND_IRIS_TRY_ONE_OVERWORLD_VANILLA_FLAT_THEEND,
-            COMMAND_IRIS_WORLD_STAGING_COMPLETED_RESTART_SERVER_GENERATE_LOAD,
+            COMMAND_IRIS_WORLD_STAGING_COMPLETED_RESTARTING_SERVER_GENERATE_LOAD,
             COMMAND_IRIS_EXCEPTION_RAISED_DURING_CREATION_SEE_CONSOLE_MORE_DETAILS,
             COMMAND_IRIS_SUCCESSFULLY_CREATED_YOUR_WORLD,
-            COMMAND_IRIS_YOUR_WORLD_WILL_AUTOMATICALLY_BE_SET_AS_MAIN_WORLD_WHEN,
             COMMAND_IRIS_RUNTIME_WORLD_CREATION_IS_DISABLED_ON_FOLIA,
             COMMAND_IRIS_PREPARING_WORLD_FILES_BUKKIT_YML_NEXT_STARTUP,
             COMMAND_IRIS_FAILED_STAGE_WORLD_FILES_DIMENSION,
-            COMMAND_IRIS_UPDATED_SERVER_PROPERTIES_LEVEL_NAME,
-            COMMAND_IRIS_WORLD_WAS_STAGED_BUT_FAILED_UPDATE_SERVER_PROPERTIES_MAIN_WORLD,
             COMMAND_IRIS_STAGED_IRIS_WORLD_WITH_GENERATOR_IRIS_SEED,
-            COMMAND_IRIS_THIS_WORLD_IS_NOW_CONFIGURED_AS_MAIN_NEXT_RESTART,
             COMMAND_IRIS_FAILED_UPDATE_BUKKIT_YML,
             COMMAND_IRIS_SPECIFIED_PLAYER_DOES_NOT_EXIST,
             COMMAND_IRIS_IRIS_V_BY_VOLMIT_SOFTWARE,

core/src/main/java/art/arcane/iris/core/localization/DirectorCommandMessages.java

@@ -282,10 +282,6 @@ public final class DirectorCommandMessages {
             "iris.director.commandiris.param.seed_generate_world_with",
             "The seed to generate the world with"
     );
-    public static final TextKey COMMAND_IRIS_PARAM_WHETHER_NOT_AUTOMATICALLY_USE_THIS_WORLD_AS_MAIN_WORLD = TextKey.of(
-            "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world",
-            "Whether or not to automatically use this world as the main world"
-    );
     public static final TextKey COMMAND_IRIS_PARAM_REPLACE_EXACT_EXISTING_WORLD_SLOT_NEXT_RESTART = TextKey.of(
             "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart",
             "Replace the exact existing world slot on the next restart"
@@ -941,7 +937,6 @@ public final class DirectorCommandMessages {
             COMMAND_IRIS_PARAM_NAME_WORLD_CREATE,
             COMMAND_IRIS_PARAM_DIMENSION_PACK_CREATE_WORLD_WITH,
             COMMAND_IRIS_PARAM_SEED_GENERATE_WORLD_WITH,
-            COMMAND_IRIS_PARAM_WHETHER_NOT_AUTOMATICALLY_USE_THIS_WORLD_AS_MAIN_WORLD,
             COMMAND_IRIS_PARAM_REPLACE_EXACT_EXISTING_WORLD_SLOT_NEXT_RESTART,
             COMMAND_IRIS_DIRECTOR_TELEPORT_ANOTHER_WORLD,
             COMMAND_IRIS_PARAM_WORLD_TELEPORT,

core/src/main/java/art/arcane/iris/core/nms/INMSBinding.java

@@ -54,6 +54,8 @@ import org.bukkit.generator.ChunkGenerator;
 import org.bukkit.inventory.ItemStack;
 
 import java.awt.Color;
+import java.io.IOException;
+import java.nio.file.Path;
 import java.util.List;
 import java.util.Set;
 import java.util.concurrent.CompletableFuture;
@@ -269,6 +271,14 @@ public interface INMSBinding {
     default void uninjectBukkit() {
     }
 
+    default void writeCurrentPaperWorldData(
+            Path sourceWorldDirectory,
+            Path targetWorldDirectory,
+            long seed
+    ) throws IOException {
+        throw new UnsupportedOperationException("The active NMS binding does not support current Paper world data staging.");
+    }
+
     KMap<Material, List<BlockProperty>> getBlockProperties();
 
     private void validateDimensionTypes(WorldCreator c) {

core/src/main/java/art/arcane/iris/core/pack/AtomicDirectoryPublisher.java

@@ -2,6 +2,7 @@ package art.arcane.iris.core.pack;
 
 import java.io.IOException;
 import java.nio.file.AtomicMoveNotSupportedException;
+import java.nio.file.FileAlreadyExistsException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
@@ -44,6 +45,22 @@ public final class AtomicDirectoryPublisher {
         }
     }
 
+    public static Publication publishAbsent(Path stagedDirectory, Path targetDirectory) throws IOException {
+        Path staged = Objects.requireNonNull(stagedDirectory, "stagedDirectory").toAbsolutePath().normalize();
+        Path target = Objects.requireNonNull(targetDirectory, "targetDirectory").toAbsolutePath().normalize();
+        if (!Files.isDirectory(staged) || Files.isSymbolicLink(staged)) {
+            throw new IOException("Staged directory is missing or unsafe: " + staged);
+        }
+        if (!Objects.equals(staged.getParent(), target.getParent())) {
+            throw new IOException("Staged and target directories must have the same parent.");
+        }
+        if (Files.exists(target) || Files.isSymbolicLink(target)) {
+            throw new FileAlreadyExistsException("Publication target already exists: " + target);
+        }
+        move(staged, target);
+        return new Publication(target, null);
+    }
+
     private static void move(Path source, Path target) throws IOException {
         try {
             Files.move(source, target, StandardCopyOption.ATOMIC_MOVE);

core/src/main/java/art/arcane/iris/core/pack/DefaultPackBootstrapProvisioner.java

@@ -2,6 +2,8 @@ package art.arcane.iris.core.pack;
 
 import art.arcane.iris.core.IrisDatapackCompiler;
 import art.arcane.iris.core.lifecycle.BukkitStartupPaths;
+import art.arcane.iris.core.lifecycle.BukkitWorldConfiguration;
+import art.arcane.iris.core.lifecycle.BukkitWorldConfiguration.IrisGeneratorBinding;
 import art.arcane.iris.core.nms.datapack.DataVersion;
 import art.arcane.iris.core.nms.datapack.IDataFixer;
 import art.arcane.volmlib.util.collection.KList;
@@ -45,7 +47,7 @@ import java.util.zip.ZipInputStream;
 public final class DefaultPackBootstrapProvisioner {
     private static final List<PackSpec> DEFAULT_PACKS = List.of();
     private static final String WORLD_DATAPACK_DIRECTORY = "iris";
-    private static final int MARKER_SCHEMA = 5;
+    private static final int MARKER_SCHEMA = 6;
     private static final int MAX_ARCHIVE_ENTRIES = 100_000;
     private static final long MAX_ARCHIVE_BYTES = 512L * 1024L * 1024L;
     private static final long MAX_EXPANDED_BYTES = 2L * 1024L * 1024L * 1024L;
@@ -71,13 +73,20 @@ public final class DefaultPackBootstrapProvisioner {
     ) throws IOException {
         Objects.requireNonNull(dataDirectory, "dataDirectory");
         Objects.requireNonNull(feedback, "feedback");
-        Path levelRoot = Objects.requireNonNull(startupPaths, "startupPaths").levelRoot();
+        BukkitStartupPaths requiredStartupPaths = Objects.requireNonNull(startupPaths, "startupPaths");
+        Path levelRoot = requiredStartupPaths.levelRoot();
+        List<IrisGeneratorBinding> bindings = BukkitWorldConfiguration.readIrisGeneratorBindings(
+                requiredStartupPaths.bukkitConfiguration().toFile(),
+                levelId(levelRoot),
+                requiredStartupPaths.levelRoot()
+        );
         HttpClient client = HttpClient.newBuilder()
                 .connectTimeout(Duration.ofSeconds(15))
                 .followRedirects(HttpClient.Redirect.ALWAYS)
                 .build();
         ProvisionOptions options = new ProvisionOptions(
                 DEFAULT_PACKS,
+                bindings,
                 client,
                 Clock.systemUTC(),
                 Duration.ofMinutes(30),
@@ -95,20 +104,24 @@ public final class DefaultPackBootstrapProvisioner {
             return false;
         }
         try {
-            return isProvisioned(
-                    dataDirectory,
-                    BukkitStartupPaths.resolveCurrent().levelRoot()
+            BukkitStartupPaths startupPaths = BukkitStartupPaths.resolveCurrent();
+            List<IrisGeneratorBinding> bindings = BukkitWorldConfiguration.readIrisGeneratorBindings(
+                    startupPaths.bukkitConfiguration().toFile(),
+                    levelId(startupPaths.levelRoot()),
+                    startupPaths.levelRoot()
             );
+            return isProvisioned(dataDirectory, startupPaths.levelRoot(), DEFAULT_PACKS, bindings);
         } catch (IOException | RuntimeException exception) {
             return false;
         }
     }
 
-    static boolean isProvisioned(Path dataDirectory, Path levelRoot) {
-        return isProvisioned(dataDirectory, levelRoot, DEFAULT_PACKS);
-    }
-
-    static boolean isProvisioned(Path dataDirectory, Path levelRoot, List<PackSpec> requiredPacks) {
+    static boolean isProvisioned(
+            Path dataDirectory,
+            Path levelRoot,
+            List<PackSpec> requiredPacks,
+            List<IrisGeneratorBinding> bindings
+    ) {
         try {
             Path normalizedData = dataDirectory.toAbsolutePath().normalize();
             Path normalizedLevel = levelRoot.toAbsolutePath().normalize();
@@ -137,12 +150,19 @@ public final class DefaultPackBootstrapProvisioner {
                     return false;
                 }
             }
-            return directoryFingerprint(datapackRoot).equals(marker.getProperty("datapackFingerprint"))
-                    && datapackRoot.toString().equals(marker.getProperty("datapackPath"))
-                    && packRootsFingerprint(IrisDatapackCompiler.collectPackRoots(
+            List<File> packRoots = IrisDatapackCompiler.collectPackRoots(
                     normalizedData,
                     normalizedLevel
-                    )).equals(marker.getProperty("aggregateFingerprint"));
+            );
+            return directoryFingerprint(datapackRoot).equals(marker.getProperty("datapackFingerprint"))
+                    && datapackRoot.toString().equals(marker.getProperty("datapackPath"))
+                    && packRootsFingerprint(packRoots).equals(marker.getProperty("aggregateFingerprint"))
+                    && IrisDatapackCompiler.computeInputFingerprint(
+                            packRoots,
+                            bindings,
+                            fixer,
+                            false
+                    ).equals(marker.getProperty("compilerInputFingerprint"));
         } catch (IOException | RuntimeException exception) {
             return false;
         }
@@ -234,10 +254,17 @@ public final class DefaultPackBootstrapProvisioner {
             }
             String compilerIdentity = IrisDatapackCompiler.compilerIdentity(fixer);
             String aggregateFingerprint = packRootsFingerprint(packRoots);
+            String compilerInputFingerprint = IrisDatapackCompiler.computeInputFingerprint(
+                    packRoots,
+                    options.bindings(),
+                    fixer,
+                    false
+            );
             boolean anyPackReplaced = !packPublications.isEmpty();
             boolean rebuildDatapack = anyPackReplaced
                     || !existingDatapack
                     || !aggregateFingerprint.equals(previousMarker.getProperty("aggregateFingerprint"))
+                    || !compilerInputFingerprint.equals(previousMarker.getProperty("compilerInputFingerprint"))
                     || !compilerIdentity.equals(previousMarker.getProperty("compilerIdentity"))
                     || !datapackRoot.toString().equals(previousMarker.getProperty("datapackPath"))
                     || !directoryFingerprint(datapackRoot).equals(previousMarker.getProperty("datapackFingerprint"));
@@ -245,7 +272,7 @@ public final class DefaultPackBootstrapProvisioner {
                 compileContainer = datapacksRoot.resolve("." + WORLD_DATAPACK_DIRECTORY + "-stage-" + UUID.randomUUID());
                 Files.createDirectories(compileContainer);
                 KList<File> outputFolders = new KList<File>().qadd(compileContainer.toFile());
-                IrisDatapackCompiler.compile(packRoots, outputFolders, fixer, false);
+                IrisDatapackCompiler.compile(packRoots, outputFolders, options.bindings(), fixer, false);
                 if (!isDatapackRoot(compileContainer, !packRoots.isEmpty())) {
                     throw new IOException("Canonical Iris datapack compiler produced incomplete output at " + compileContainer);
                 }
@@ -266,6 +293,7 @@ public final class DefaultPackBootstrapProvisioner {
             String finalAggregateFingerprint = packRootsFingerprint(finalPackRoots);
             String finalCompilerInputFingerprint = IrisDatapackCompiler.computeInputFingerprint(
                     finalPackRoots,
+                    options.bindings(),
                     fixer,
                     false);
             String finalDatapackFingerprint = directoryFingerprint(datapackRoot);
@@ -280,6 +308,7 @@ public final class DefaultPackBootstrapProvisioner {
             }
             marker.setProperty("aggregateFingerprint", finalAggregateFingerprint);
             marker.setProperty("compilerIdentity", compilerIdentity);
+            marker.setProperty("compilerInputFingerprint", finalCompilerInputFingerprint);
             marker.setProperty("datapackFingerprint", finalDatapackFingerprint);
             marker.setProperty("datapackPath", datapackRoot.toString());
             marker.setProperty("completedAt", Long.toString(options.clock().millis()));
@@ -765,6 +794,14 @@ public final class DefaultPackBootstrapProvisioner {
         }
     }
 
+    private static String levelId(Path levelRoot) throws IOException {
+        Path fileName = Objects.requireNonNull(levelRoot, "levelRoot").getFileName();
+        if (fileName == null || fileName.toString().isBlank()) {
+            throw new IOException("Configured level root has no Paper startup level id: " + levelRoot);
+        }
+        return fileName.toString();
+    }
+
     private static void deleteQuietly(Path path, Consumer<String> feedback) {
         try {
             delete(path);
@@ -880,6 +917,7 @@ public final class DefaultPackBootstrapProvisioner {
 
     record ProvisionOptions(
             List<PackSpec> packs,
+            List<IrisGeneratorBinding> bindings,
             HttpClient client,
             Clock clock,
             Duration refreshInterval,
@@ -891,6 +929,7 @@ public final class DefaultPackBootstrapProvisioner {
     ) {
         ProvisionOptions {
             packs = List.copyOf(Objects.requireNonNull(packs, "packs"));
+            bindings = List.copyOf(Objects.requireNonNull(bindings, "bindings"));
             Objects.requireNonNull(client, "client");
             Objects.requireNonNull(clock, "clock");
             Objects.requireNonNull(refreshInterval, "refreshInterval");

core/src/main/java/art/arcane/iris/core/tools/IrisCreator.java

@@ -134,8 +134,11 @@ public class IrisCreator {
     private BiConsumer<String, Long> studioTimingConsumer;
     private DatapackPreparation datapackPreparation = DatapackPreparation.INSTALL_IF_CHANGED;
 
-    public static boolean removeFromBukkitYml(String name) throws IOException {
-        return BukkitWorldConfiguration.remove(BUKKIT_YML, name);
+    public static boolean removeFromBukkitYml(NamespacedKey worldKey) throws IOException {
+        return BukkitWorldConfiguration.remove(
+                BUKKIT_YML,
+                IrisWorldStorage.configuredWorldName(worldKey, IrisWorldStorage.levelRoot().getName())
+        );
     }
 
     public static int removeTransientStudioWorldsFromBukkitYml() throws IOException {
@@ -293,7 +296,12 @@ public class IrisCreator {
             reportStudioProgress(0.86D, "create_world");
 
             if (!studio && !benchmark) {
-                BukkitWorldConfiguration.register(BUKKIT_YML, name, dimension, seed);
+                BukkitWorldConfiguration.register(
+                        BUKKIT_YML,
+                        IrisWorldStorage.configuredWorldName(worldKey, IrisWorldStorage.levelRoot().getName()),
+                        dimension,
+                        seed
+                );
                 bukkitRegistered = true;
                 World createdWorld = world;
                 CompletableFuture<Void> multiverseRegistration = J.sfut(
@@ -730,7 +738,10 @@ public class IrisCreator {
                 failure.addSuppressed(rollbackFailure);
             }
             try {
-                BukkitWorldConfiguration.remove(BUKKIT_YML, name);
+                BukkitWorldConfiguration.remove(
+                        BUKKIT_YML,
+                        IrisWorldStorage.configuredWorldName(worldKey, IrisWorldStorage.levelRoot().getName())
+                );
             } catch (Throwable rollbackFailure) {
                 failure.addSuppressed(rollbackFailure);
             }

core/src/main/java/art/arcane/iris/core/tools/IrisToolbelt.java

@@ -670,7 +670,7 @@ public class IrisToolbelt {
     }
 
     public static boolean removeWorld(World world) throws IOException {
-        return IrisCreator.removeFromBukkitYml(IrisWorldStorage.logicalName(world));
+        return IrisCreator.removeFromBukkitYml(WorldIdentity.key(world));
     }
 
     record PackReference(String pack, String dimension, boolean explicitDimension) {

core/src/main/resources/languages/de_DE.json

@@ -149,17 +149,13 @@
     "iris.bukkit.commandiris.may_we_suggest_name_irisworld_instead_2": "§cWie wäre es stattdessen mit dem Namen \"IrisWorld\"?",
     "iris.bukkit.commandiris.that_folder_already_exists": "§cDieser Ordner existiert bereits!",
     "iris.bukkit.commandiris.try_one_overworld_vanilla_flat_theend": "§eVersuche eine der folgenden Optionen: overworld, vanilla, flat, theend",
-    "iris.bukkit.commandiris.world_staging_completed_restart_server_generate_load": "§aVorbereitung der Welt abgeschlossen. Starte den Server neu, um \"{worldName}\" zu generieren/zu laden.",
+    "iris.bukkit.commandiris.world_staging_completed_restarting_server_generate_load": "§aVorbereitung der Welt abgeschlossen. Iris startet den Server jetzt neu, um \"{worldName}\" zu generieren/zu laden.",
     "iris.bukkit.commandiris.exception_raised_during_creation_see_console_more_details": "§cBei der Erstellung ist eine Ausnahme aufgetreten. Weitere Details findest du in der Konsole.",
     "iris.bukkit.commandiris.successfully_created_your_world": "§aDeine Welt wurde erfolgreich erstellt!",
-    "iris.bukkit.commandiris.your_world_will_automatically_be_set_as_main_world_when": "§aIhre Welt wird automatisch als Hauptwelt festgelegt, wenn der Server neu gestartet wird.",
     "iris.bukkit.commandiris.runtime_world_creation_is_disabled_on_folia": "§eDie Erstellung von Welten zur Laufzeit ist unter Folia deaktiviert.",
     "iris.bukkit.commandiris.preparing_world_files_bukkit_yml_next_startup": "§eWeltdateien und bukkit.yml werden für den nächsten Start vorbereitet...",
     "iris.bukkit.commandiris.failed_stage_world_files_dimension": "§cDie Weltdateien für Dimension \"{value}\" konnten nicht vorbereitet werden.",
-    "iris.bukkit.commandiris.updated_server_properties_level_name": "§aDie Eigenschaft level-name in server.properties wurde auf \"{name}\" gesetzt.",
-    "iris.bukkit.commandiris.world_was_staged_but_failed_update_server_properties_main_world": "§cDie Welt wurde vorbereitet, aber die Hauptwelt in server.properties konnte nicht aktualisiert werden.",
     "iris.bukkit.commandiris.staged_iris_world_with_generator_iris_seed": "§aIris-Welt \"{name}\" mit Generator Iris:{value} und Seed {seed} vorbereitet.",
-    "iris.bukkit.commandiris.this_world_is_now_configured_as_main_next_restart": "§aDiese Welt ist für den nächsten Neustart als Hauptwelt konfiguriert.",
     "iris.bukkit.commandiris.failed_update_bukkit_yml": "§cbukkit.yml konnte nicht aktualisiert werden: {value}",
     "iris.bukkit.commandiris.specified_player_does_not_exist": "§cDer angegebene Spieler existiert nicht.",
     "iris.bukkit.commandiris.iris_v_by_volmit_software": "§aIris v{value} von Volmit Software",
@@ -693,7 +689,6 @@
     "iris.director.commandiris.param.name_world_create": "Name der zu erstellenden Welt",
     "iris.director.commandiris.param.dimension_pack_create_world_with": "Dimension oder Pack, mit der bzw. dem die Welt erstellt wird",
     "iris.director.commandiris.param.seed_generate_world_with": "Seed für die Generierung der Welt",
-    "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world": "Ob man diese Welt automatisch als Hauptwelt benutzt oder nicht",
     "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart": "Den exakten vorhandenen Welt-Slot beim nächsten Neustart ersetzen",
     "iris.director.commandiris.director.teleport_another_world": "Teleportieren in eine andere Welt",
     "iris.director.commandiris.param.world_teleport": "Zielwelt der Teleportation",

core/src/main/resources/languages/es_ES.json

@@ -149,17 +149,13 @@
     "iris.bukkit.commandiris.may_we_suggest_name_irisworld_instead_2": "§c¿Podemos sugerir el nombre \"IrisWorld\"?",
     "iris.bukkit.commandiris.that_folder_already_exists": "§c¡Esa carpeta ya existe!",
     "iris.bukkit.commandiris.try_one_overworld_vanilla_flat_theend": "§ePrueba una de estas opciones: overworld, vanilla, flat, theend",
-    "iris.bukkit.commandiris.world_staging_completed_restart_server_generate_load": "§aPreparación del mundo completada. Reinicia el servidor para generar/cargar \"{worldName}\".",
+    "iris.bukkit.commandiris.world_staging_completed_restarting_server_generate_load": "§aPreparación del mundo completada. Iris está reiniciando el servidor para generar/cargar \"{worldName}\".",
     "iris.bukkit.commandiris.exception_raised_during_creation_see_console_more_details": "§cSe produjo una excepción durante la creación. Consulta la consola para obtener más detalles.",
     "iris.bukkit.commandiris.successfully_created_your_world": "§a¡Tu mundo se creó correctamente!",
-    "iris.bukkit.commandiris.your_world_will_automatically_be_set_as_main_world_when": "§aTu mundo se establecerá automáticamente como mundo principal cuando se reinicie el servidor.",
     "iris.bukkit.commandiris.runtime_world_creation_is_disabled_on_folia": "§eLa creación de mundos en tiempo de ejecución está desactivada en Folia.",
     "iris.bukkit.commandiris.preparing_world_files_bukkit_yml_next_startup": "§ePreparando los archivos del mundo y bukkit.yml para el próximo inicio...",
     "iris.bukkit.commandiris.failed_stage_world_files_dimension": "§cNo se pudieron preparar los archivos del mundo para la dimensión \"{value}\".",
-    "iris.bukkit.commandiris.updated_server_properties_level_name": "§aSe actualizó level-name en server.properties a \"{name}\".",
-    "iris.bukkit.commandiris.world_was_staged_but_failed_update_server_properties_main_world": "§cEl mundo se preparó, pero no se pudo actualizar el mundo principal en server.properties.",
     "iris.bukkit.commandiris.staged_iris_world_with_generator_iris_seed": "§aSe preparó el mundo de Iris \"{name}\" con el generador Iris:{value} y la semilla {seed}.",
-    "iris.bukkit.commandiris.this_world_is_now_configured_as_main_next_restart": "§aEste mundo está configurado como principal para el próximo reinicio.",
     "iris.bukkit.commandiris.failed_update_bukkit_yml": "§cNo se pudo actualizar bukkit.yml: {value}",
     "iris.bukkit.commandiris.specified_player_does_not_exist": "§cEl jugador especificado no existe.",
     "iris.bukkit.commandiris.iris_v_by_volmit_software": "§aIris v{value} por Volmit Software",
@@ -693,7 +689,6 @@
     "iris.director.commandiris.param.name_world_create": "El nombre del mundo que se creará",
     "iris.director.commandiris.param.dimension_pack_create_world_with": "La dimensión o el pack con el que se creará el mundo",
     "iris.director.commandiris.param.seed_generate_world_with": "La semilla con la que se generará el mundo",
-    "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world": "Indica si este mundo debe usarse automáticamente como mundo principal",
     "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart": "Reemplazar el espacio exacto del mundo existente en el próximo reinicio",
     "iris.director.commandiris.director.teleport_another_world": "Teletransportarse a otro mundo",
     "iris.director.commandiris.param.world_teleport": "El mundo al que se teletransportará",

core/src/main/resources/languages/fi_FI.json

@@ -149,17 +149,13 @@
     "iris.bukkit.commandiris.may_we_suggest_name_irisworld_instead_2": "§cVoimmeko ehdottaa nimeä \"IrisWorldSen sijaan?",
     "iris.bukkit.commandiris.that_folder_already_exists": "§cSe kansio on jo olemassa!",
     "iris.bukkit.commandiris.try_one_overworld_vanilla_flat_theend": "§eKokeile yksi: maapallo, vanilla, litteä, theend",
-    "iris.bukkit.commandiris.world_staging_completed_restart_server_generate_load": "§aMaailman valmistelu valmis. Käynnistä palvelin uudelleen, jotta \"{worldName}\" luodaan/ladataan.",
+    "iris.bukkit.commandiris.world_staging_completed_restarting_server_generate_load": "§aMaailman valmistelu valmis. Iris käynnistää palvelimen nyt uudelleen, jotta \"{worldName}\" luodaan/ladataan.",
     "iris.bukkit.commandiris.exception_raised_during_creation_see_console_more_details": "§cLuomisen aikana nostettu poikkeus.  Katso lisätietoja konsolista.",
     "iris.bukkit.commandiris.successfully_created_your_world": "§aOnnistuneesti loin maailmasi!",
-    "iris.bukkit.commandiris.your_world_will_automatically_be_set_as_main_world_when": "§aMaailmasi asetetaan automaattisesti päämaailmaksi, kun palvelin käynnistyy uudelleen.",
     "iris.bukkit.commandiris.runtime_world_creation_is_disabled_on_folia": "§eRuntime maailman luominen on pois käytöstä Folia.",
     "iris.bukkit.commandiris.preparing_world_files_bukkit_yml_next_startup": "§eValmistellaan maailman tiedostoja ja bukkit.yml seuraavan käynnistyksen...",
     "iris.bukkit.commandiris.failed_stage_world_files_dimension": "§cMaailmatiedostoja ei voitu lavastaa ulottuvuudeksi \"{value}\".",
-    "iris.bukkit.commandiris.updated_server_properties_level_name": "§aPäivitetty server.properties tason nimi \"{name}\".",
-    "iris.bukkit.commandiris.world_was_staged_but_failed_update_server_properties_main_world": "§cMaailma lavastettiin, mutta sitä ei päivitetty server.properties suurmaailma.",
     "iris.bukkit.commandiris.staged_iris_world_with_generator_iris_seed": "§aIris-maailma \"{name}\" valmisteltiin generaattorilla Iris:{value} ja siemenellä {seed}.",
-    "iris.bukkit.commandiris.this_world_is_now_configured_as_main_next_restart": "§aTämä maailma on nyt asetettu pääohjelmaksi seuraavaan uudelleenkäynnistykseen.",
     "iris.bukkit.commandiris.failed_update_bukkit_yml": "§cPäivitys epäonnistui bukkit.yml: {value}",
     "iris.bukkit.commandiris.specified_player_does_not_exist": "§cMääriteltyä pelaajaa ei ole olemassa.",
     "iris.bukkit.commandiris.iris_v_by_volmit_software": "§aIris{value} mennessä Volmit Software",
@@ -693,7 +689,6 @@
     "iris.director.commandiris.param.name_world_create": "Luotavan maailman nimi",
     "iris.director.commandiris.param.dimension_pack_create_world_with": "Ulottuvuus / paketti luoda maailma",
     "iris.director.commandiris.param.seed_generate_world_with": "Siemenet tuottaa maailman kanssa",
-    "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world": "Käytetäänkö tätä maailmaa automaattisesti päämaailmana",
     "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart": "Korvaa täsmällinen olemassa oleva maailmapaikka seuraavalla uudelleenkäynnistyksellä",
     "iris.director.commandiris.director.teleport_another_world": "Teleporttautuminen toiseen maailmaan",
     "iris.director.commandiris.param.world_teleport": "Maailman teleportata",

core/src/main/resources/languages/fr_FR.json

@@ -149,17 +149,13 @@
     "iris.bukkit.commandiris.may_we_suggest_name_irisworld_instead_2": "§cNous vous suggérons plutôt le nom \"IrisWorld\".",
     "iris.bukkit.commandiris.that_folder_already_exists": "§cCe dossier existe déjà !",
     "iris.bukkit.commandiris.try_one_overworld_vanilla_flat_theend": "§eEssayez l'une des options suivantes : overworld, vanilla, flat, theend",
-    "iris.bukkit.commandiris.world_staging_completed_restart_server_generate_load": "§aPréparation du monde terminée. Redémarrez le serveur pour générer/charger \"{worldName}\".",
+    "iris.bukkit.commandiris.world_staging_completed_restarting_server_generate_load": "§aPréparation du monde terminée. Iris redémarre maintenant le serveur pour générer/charger \"{worldName}\".",
     "iris.bukkit.commandiris.exception_raised_during_creation_see_console_more_details": "§cUne exception s'est produite pendant la création. Consultez la console pour plus de détails.",
     "iris.bukkit.commandiris.successfully_created_your_world": "§aVotre monde a été créé avec succès !",
-    "iris.bukkit.commandiris.your_world_will_automatically_be_set_as_main_world_when": "§aVotre monde deviendra automatiquement le monde principal au redémarrage du serveur.",
     "iris.bukkit.commandiris.runtime_world_creation_is_disabled_on_folia": "§eLa création de mondes pendant l'exécution est désactivée sur Folia.",
     "iris.bukkit.commandiris.preparing_world_files_bukkit_yml_next_startup": "§ePréparation des fichiers du monde et de bukkit.yml pour le prochain démarrage...",
     "iris.bukkit.commandiris.failed_stage_world_files_dimension": "§cImpossible de préparer les fichiers du monde pour la dimension \"{value}\".",
-    "iris.bukkit.commandiris.updated_server_properties_level_name": "§aLa propriété level-name de server.properties a été définie sur \"{name}\".",
-    "iris.bukkit.commandiris.world_was_staged_but_failed_update_server_properties_main_world": "§cLe monde a été préparé, mais le monde principal n'a pas pu être mis à jour dans server.properties.",
     "iris.bukkit.commandiris.staged_iris_world_with_generator_iris_seed": "§aLe monde Iris \"{name}\" a été préparé avec le générateur Iris:{value} et la graine {seed}.",
-    "iris.bukkit.commandiris.this_world_is_now_configured_as_main_next_restart": "§aCe monde est maintenant configuré comme monde principal pour le prochain redémarrage.",
     "iris.bukkit.commandiris.failed_update_bukkit_yml": "§cImpossible de mettre à jour bukkit.yml : {value}",
     "iris.bukkit.commandiris.specified_player_does_not_exist": "§cLe joueur indiqué n'existe pas.",
     "iris.bukkit.commandiris.iris_v_by_volmit_software": "§aIris v{value} par Volmit Software",
@@ -693,7 +689,6 @@
     "iris.director.commandiris.param.name_world_create": "Le nom du monde à créer",
     "iris.director.commandiris.param.dimension_pack_create_world_with": "La dimension ou le pack avec lequel créer le monde",
     "iris.director.commandiris.param.seed_generate_world_with": "La graine avec laquelle générer le monde",
-    "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world": "Indique si ce monde doit être utilisé automatiquement comme monde principal",
     "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart": "Remplacer l’emplacement exact du monde existant au prochain redémarrage",
     "iris.director.commandiris.director.teleport_another_world": "Se téléporter vers un autre monde",
     "iris.director.commandiris.param.world_teleport": "Le monde vers lequel se téléporter",

core/src/main/resources/languages/he_IL.json

@@ -149,17 +149,13 @@
     "iris.bukkit.commandiris.may_we_suggest_name_irisworld_instead_2": "§cאפשר להציע את השם \"IrisWorld\"במקום?",
     "iris.bukkit.commandiris.that_folder_already_exists": "§cהתיקיה הזו כבר קיימת!",
     "iris.bukkit.commandiris.try_one_overworld_vanilla_flat_theend": "§eנסה: Overworld vanilla, שטוח, TheendXTry",
-    "iris.bukkit.commandiris.world_staging_completed_restart_server_generate_load": "§aהכנת העולם הושלמה. הפעל מחדש את השרת כדי ליצור/לטעון את \"{worldName}\".",
+    "iris.bukkit.commandiris.world_staging_completed_restarting_server_generate_load": "§aהכנת העולם הושלמה. Iris מפעיל כעת מחדש את השרת כדי ליצור/לטעון את \"{worldName}\".",
     "iris.bukkit.commandiris.exception_raised_during_creation_see_console_more_details": "§cלמעטים שגדלו במהלך הבריאה.  ראו את הקונסולה לפרטים נוספים.",
     "iris.bukkit.commandiris.successfully_created_your_world": "§aיצרתם בהצלחה את עולמכם!",
-    "iris.bukkit.commandiris.your_world_will_automatically_be_set_as_main_world_when": "§aעולמכם יקבע באופן אוטומטי כעולם הראשי כאשר השרת נפתח מחדש.",
     "iris.bukkit.commandiris.runtime_world_creation_is_disabled_on_folia": "§eיצירת העולם של Runtime זמינה Folia.",
     "iris.bukkit.commandiris.preparing_world_files_bukkit_yml_next_startup": "§eהכנת קבצים בעולם bukkit.yml עבור הסטארט-אפ הבא...",
     "iris.bukkit.commandiris.failed_stage_world_files_dimension": "§cנכשלים בקבצי עולם הבמה לממד \"{value}\".",
-    "iris.bukkit.commandiris.updated_server_properties_level_name": "§aעדכון server.properties שם ברמה \"{name}\".",
-    "iris.bukkit.commandiris.world_was_staged_but_failed_update_server_properties_main_world": "§cהעולם הוטבע, אך לא הצליח לעדכן server.properties העולם הראשי",
     "iris.bukkit.commandiris.staged_iris_world_with_generator_iris_seed": "§aעולם Iris ‏\"{name}\" הוכן עם המחולל Iris:{value} והזרע {seed}.",
-    "iris.bukkit.commandiris.this_world_is_now_configured_as_main_next_restart": "§aהעולם הזה מוגדר כעת כעיקרי לחידוש הבא.",
     "iris.bukkit.commandiris.failed_update_bukkit_yml": "§cנכשל לעדכן bukkit.yml: {value}",
     "iris.bukkit.commandiris.specified_player_does_not_exist": "§cהשחקן שצוין אינו קיים.",
     "iris.bukkit.commandiris.iris_v_by_volmit_software": "§aאיריס v{value} על ידי Volmit Software",
@@ -693,7 +689,6 @@
     "iris.director.commandiris.param.name_world_create": "שם העולם ליצור",
     "iris.director.commandiris.param.dimension_pack_create_world_with": "המימד / החבילה ליצירת העולם עם",
     "iris.director.commandiris.param.seed_generate_world_with": "הזרע ליצור את העולם עם",
-    "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world": "בין אם להשתמש בעולם באופן אוטומטי כעולם הראשי",
     "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart": "החלפת משבצת העולם הקיימת המדויקת בהפעלה מחדש הבאה",
     "iris.director.commandiris.director.teleport_another_world": "טלפורט לעולם אחר",
     "iris.director.commandiris.param.world_teleport": "העולם לטלפורט",

core/src/main/resources/languages/it_IT.json

@@ -149,17 +149,13 @@
     "iris.bukkit.commandiris.may_we_suggest_name_irisworld_instead_2": "§cPossiamo suggerire il nome \"IrisWorld\" invece?",
     "iris.bukkit.commandiris.that_folder_already_exists": "§cQuella cartella esiste già!",
     "iris.bukkit.commandiris.try_one_overworld_vanilla_flat_theend": "§eProva una delle seguenti opzioni: overworld, vanilla, flat, theend",
-    "iris.bukkit.commandiris.world_staging_completed_restart_server_generate_load": "§aPreparazione del mondo completata. Riavvia il server per generare/caricare \"{worldName}\".",
+    "iris.bukkit.commandiris.world_staging_completed_restarting_server_generate_load": "§aPreparazione del mondo completata. Iris sta riavviando il server per generare/caricare \"{worldName}\".",
     "iris.bukkit.commandiris.exception_raised_during_creation_see_console_more_details": "§cSi è verificata un'eccezione durante la creazione. Consulta la console per maggiori dettagli.",
     "iris.bukkit.commandiris.successfully_created_your_world": "§aCreato con successo il tuo mondo!",
-    "iris.bukkit.commandiris.your_world_will_automatically_be_set_as_main_world_when": "§aIl tuo mondo verrà impostato automaticamente come mondo principale al riavvio del server.",
     "iris.bukkit.commandiris.runtime_world_creation_is_disabled_on_folia": "§eLa creazione di mondi durante l'esecuzione è disattivata su Folia.",
     "iris.bukkit.commandiris.preparing_world_files_bukkit_yml_next_startup": "§ePreparazione dei file del mondo e di bukkit.yml per il prossimo avvio...",
     "iris.bukkit.commandiris.failed_stage_world_files_dimension": "§cImpossibile preparare i file del mondo per la dimensione \"{value}\".",
-    "iris.bukkit.commandiris.updated_server_properties_level_name": "§aLa proprietà level-name in server.properties è stata impostata su \"{name}\".",
-    "iris.bukkit.commandiris.world_was_staged_but_failed_update_server_properties_main_world": "§cIl mondo è stato preparato, ma non è stato possibile aggiornare il mondo principale in server.properties.",
     "iris.bukkit.commandiris.staged_iris_world_with_generator_iris_seed": "§aMondo Iris \"{name}\" preparato con il generatore Iris:{value} e il seed {seed}.",
-    "iris.bukkit.commandiris.this_world_is_now_configured_as_main_next_restart": "§aQuesto mondo è ora configurato come principale per il prossimo riavvio.",
     "iris.bukkit.commandiris.failed_update_bukkit_yml": "§cImpossibile aggiornare bukkit.yml: {value}",
     "iris.bukkit.commandiris.specified_player_does_not_exist": "§cIl giocatore specificato non esiste.",
     "iris.bukkit.commandiris.iris_v_by_volmit_software": "§aIris v{value} di Volmit Software",
@@ -693,7 +689,6 @@
     "iris.director.commandiris.param.name_world_create": "Il nome del mondo da creare",
     "iris.director.commandiris.param.dimension_pack_create_world_with": "La dimensione o il Pack con cui creare il mondo",
     "iris.director.commandiris.param.seed_generate_world_with": "Il seed con cui generare il mondo",
-    "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world": "Che sia o meno utilizzare automaticamente questo mondo come il mondo principale",
     "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart": "Sostituisci lo slot esatto del mondo esistente al prossimo riavvio",
     "iris.director.commandiris.director.teleport_another_world": "Teletrasporto in un altro mondo",
     "iris.director.commandiris.param.world_teleport": "Il mondo verso cui teletrasportarsi",

core/src/main/resources/languages/ja-JP.json

@@ -149,17 +149,13 @@
     "iris.bukkit.commandiris.may_we_suggest_name_irisworld_instead_2": "§c代わりに \"IrisWorld\" という名前はいかがですか?",
     "iris.bukkit.commandiris.that_folder_already_exists": "§cそのフォルダーはすでに存在します!",
     "iris.bukkit.commandiris.try_one_overworld_vanilla_flat_theend": "§e次のいずれかを指定してください: overworld、vanilla、flat、theend",
-    "iris.bukkit.commandiris.world_staging_completed_restart_server_generate_load": "§aワールドの準備が完了しました。\"{worldName}\" を生成/読み込むにはサーバーを再起動してください。",
+    "iris.bukkit.commandiris.world_staging_completed_restarting_server_generate_load": "§aワールドの準備が完了しました。Iris は \"{worldName}\" を生成/読み込むためにサーバーを再起動しています。",
     "iris.bukkit.commandiris.exception_raised_during_creation_see_console_more_details": "§c作成中に例外が発生しました。詳細はコンソールを確認してください。",
     "iris.bukkit.commandiris.successfully_created_your_world": "§aワールドを作成しました!",
-    "iris.bukkit.commandiris.your_world_will_automatically_be_set_as_main_world_when": "§aサーバーを再起動すると、このワールドが自動的にメインワールドに設定されます。",
     "iris.bukkit.commandiris.runtime_world_creation_is_disabled_on_folia": "§eFolia では実行中のワールド作成が無効です。",
     "iris.bukkit.commandiris.preparing_world_files_bukkit_yml_next_startup": "§e次回起動用のワールドファイルと bukkit.yml を準備しています...",
     "iris.bukkit.commandiris.failed_stage_world_files_dimension": "§cディメンション \"{value}\" のワールドファイルを準備できませんでした。",
-    "iris.bukkit.commandiris.updated_server_properties_level_name": "§aserver.properties の level-name を \"{name}\" に更新しました。",
-    "iris.bukkit.commandiris.world_was_staged_but_failed_update_server_properties_main_world": "§cワールドは準備されましたが、server.properties のメインワールド設定を更新できませんでした。",
     "iris.bukkit.commandiris.staged_iris_world_with_generator_iris_seed": "§aIris ワールド \"{name}\" をジェネレーター Iris:{value}、シード {seed} で準備しました。",
-    "iris.bukkit.commandiris.this_world_is_now_configured_as_main_next_restart": "§aこのワールドは、次回再起動時のメインワールドとして設定されました。",
     "iris.bukkit.commandiris.failed_update_bukkit_yml": "§cbukkit.yml を更新できませんでした: {value}",
     "iris.bukkit.commandiris.specified_player_does_not_exist": "§c指定されたプレイヤーは存在しません。",
     "iris.bukkit.commandiris.iris_v_by_volmit_software": "§aIris v{value} by Volmit Software",
@@ -693,7 +689,6 @@
     "iris.director.commandiris.param.name_world_create": "作成するワールドの名前",
     "iris.director.commandiris.param.dimension_pack_create_world_with": "ワールドの作成に使用するディメンションまたはパック",
     "iris.director.commandiris.param.seed_generate_world_with": "ワールドの生成に使用するシード",
-    "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world": "このワールドをメインワールドとして自動設定するかどうか",
     "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart": "次回の再起動時に既存の正確なワールドスロットを置き換える",
     "iris.director.commandiris.director.teleport_another_world": "別のワールドへテレポートします",
     "iris.director.commandiris.param.world_teleport": "テレポート先のワールド",

core/src/main/resources/languages/ko_KR.json

@@ -149,17 +149,13 @@
     "iris.bukkit.commandiris.may_we_suggest_name_irisworld_instead_2": "§c우리는 이름 \"을 제안 할 수있다IrisWorld\" 대신?",
     "iris.bukkit.commandiris.that_folder_already_exists": "§c그 폴더는 이미 존재합니다!",
     "iris.bukkit.commandiris.try_one_overworld_vanilla_flat_theend": "§e중 하나를 시도: overworld, 바닐라, 플랫, theend",
-    "iris.bukkit.commandiris.world_staging_completed_restart_server_generate_load": "§a월드 준비가 완료되었습니다. \"{worldName}\"을 생성/로드하려면 서버를 재시작하세요.",
+    "iris.bukkit.commandiris.world_staging_completed_restarting_server_generate_load": "§a월드 준비가 완료되었습니다. Iris가 \"{worldName}\"을 생성/로드하기 위해 서버를 재시작하고 있습니다.",
     "iris.bukkit.commandiris.exception_raised_during_creation_see_console_more_details": "§c창조 중 발생한 예외.  자세한 내용은 콘솔을 참조하십시오.",
     "iris.bukkit.commandiris.successfully_created_your_world": "§a세상을 성공적으로 만들었습니다!",
-    "iris.bukkit.commandiris.your_world_will_automatically_be_set_as_main_world_when": "§a서버가 재시작할 때 세계로 자동 설정됩니다.",
     "iris.bukkit.commandiris.runtime_world_creation_is_disabled_on_folia": "§eRuntime 세계 생성은 비활성화됩니다 Folia.",
     "iris.bukkit.commandiris.preparing_world_files_bukkit_yml_next_startup": "§e세계 파일 및 준비 bukkit.yml 다음 시작...",
     "iris.bukkit.commandiris.failed_stage_world_files_dimension": "§c차원을 위한 단계 세계 파일에 실패 \"{value}\".",
-    "iris.bukkit.commandiris.updated_server_properties_level_name": "§a으로 server.properties \"에 수평 이름{name}\".",
-    "iris.bukkit.commandiris.world_was_staged_but_failed_update_server_properties_main_world": "§c세계는 무대로, 하지만 업데이트 실패 server.properties 주요 세계.",
     "iris.bukkit.commandiris.staged_iris_world_with_generator_iris_seed": "§aIris 월드 \"{name}\"을 생성기 Iris:{value}, 시드 {seed}로 준비했습니다.",
-    "iris.bukkit.commandiris.this_world_is_now_configured_as_main_next_restart": "§a다음 재시작의 메인 월드로 설정했습니다.",
     "iris.bukkit.commandiris.failed_update_bukkit_yml": "§c업데이트 실패 bukkit.yml: {value}",
     "iris.bukkit.commandiris.specified_player_does_not_exist": "§c지정된 플레이어는 존재하지 않습니다.",
     "iris.bukkit.commandiris.iris_v_by_volmit_software": "§a아이리스 v{value} Volmit 소프트웨어",
@@ -693,7 +689,6 @@
     "iris.director.commandiris.param.name_world_create": "만들 월드 이름",
     "iris.director.commandiris.param.dimension_pack_create_world_with": "월드 생성에 사용할 차원 또는 팩",
     "iris.director.commandiris.param.seed_generate_world_with": "월드 생성에 사용할 시드",
-    "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world": "이 월드를 메인 월드로 자동 사용할지 여부",
     "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart": "다음 재시작 시 기존의 정확한 월드 슬롯 교체",
     "iris.director.commandiris.director.teleport_another_world": "다른 월드로 순간이동합니다",
     "iris.director.commandiris.param.world_teleport": "순간이동할 월드",

core/src/main/resources/languages/lt_LT.json

@@ -149,17 +149,13 @@
     "iris.bukkit.commandiris.may_we_suggest_name_irisworld_instead_2": "§cAr galime pasiūlyti pavadinimą \"IrisWorld\"vietoj to?",
     "iris.bukkit.commandiris.that_folder_already_exists": "§cTas aplankas jau egzistuoja!",
     "iris.bukkit.commandiris.try_one_overworld_vanilla_flat_theend": "§ePabandykite vieną iš: per pasaulį, vanilla, butas, pabaiga",
-    "iris.bukkit.commandiris.world_staging_completed_restart_server_generate_load": "§aPasaulio paruošimas baigtas. Paleiskite serverį iš naujo, kad sugeneruotumėte / įkeltumėte „{worldName}“.",
+    "iris.bukkit.commandiris.world_staging_completed_restarting_server_generate_load": "§aPasaulio paruošimas baigtas. Iris dabar paleidžia serverį iš naujo, kad sugeneruotų / įkeltų „{worldName}“.",
     "iris.bukkit.commandiris.exception_raised_during_creation_see_console_more_details": "§cSukūrimo metu iškelta išimtis.  Daugiau informacijos rasite konsolėje.",
     "iris.bukkit.commandiris.successfully_created_your_world": "§aSėkmingai sukūrė savo pasaulį!",
-    "iris.bukkit.commandiris.your_world_will_automatically_be_set_as_main_world_when": "§aJūsų pasaulis bus automatiškai nustatytas kaip pagrindinis pasaulis, kai serveris vėl paleidžiamas.",
     "iris.bukkit.commandiris.runtime_world_creation_is_disabled_on_folia": "§eweather forecast Folia.",
     "iris.bukkit.commandiris.preparing_world_files_bukkit_yml_next_startup": "§eRuošiami pasauliniai failai ir bukkit.yml kitam paleidimui...",
     "iris.bukkit.commandiris.failed_stage_world_files_dimension": "§cNepavyko sukurti pasaulinių matmenų failų \"{value}\".",
-    "iris.bukkit.commandiris.updated_server_properties_level_name": "§aAtnaujinta server.properties Lyginamasis pavadinimas į \"{name}\".",
-    "iris.bukkit.commandiris.world_was_staged_but_failed_update_server_properties_main_world": "§cPasaulis buvo suskirstytas, bet nepavyko atnaujinti server.properties pagrindinis pasaulis.",
     "iris.bukkit.commandiris.staged_iris_world_with_generator_iris_seed": "§aParuoštas Iris pasaulis „{name}“ su generatoriumi Iris:{value} ir pradine reikšme {seed}.",
-    "iris.bukkit.commandiris.this_world_is_now_configured_as_main_next_restart": "§aŠis pasaulis dabar yra sukonfigūruotas kaip pagrindinis kitą startą.",
     "iris.bukkit.commandiris.failed_update_bukkit_yml": "§cNepavyko atnaujinti bukkit.yml: {value}",
     "iris.bukkit.commandiris.specified_player_does_not_exist": "§cNurodytasis žaidėjas neegzistuoja.",
     "iris.bukkit.commandiris.iris_v_by_volmit_software": "§aIris prieš{value} pagal Volmit programinė įranga",
@@ -693,7 +689,6 @@
     "iris.director.commandiris.param.name_world_create": "Kuriamo pasaulio pavadinimas",
     "iris.director.commandiris.param.dimension_pack_create_world_with": "dimensija / paketas sukurti pasaulį su",
     "iris.director.commandiris.param.seed_generate_world_with": "Sėkla generuoti pasaulį su",
-    "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world": "Ar automatiškai naudoti šį pasaulį kaip pagrindinį pasaulį",
     "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart": "Per kitą paleidimą iš naujo pakeisti tikslų esamą pasaulio lizdą",
     "iris.director.commandiris.director.teleport_another_world": "Teleportas į kitą pasaulį",
     "iris.director.commandiris.param.world_teleport": "Pasaulis teleportui į",

core/src/main/resources/languages/nl_NL.json

@@ -149,17 +149,13 @@
     "iris.bukkit.commandiris.may_we_suggest_name_irisworld_instead_2": "§cMogen we de naam voorstellen \"IrisWorldIn plaats daarvan?",
     "iris.bukkit.commandiris.that_folder_already_exists": "§cDie map bestaat al!",
     "iris.bukkit.commandiris.try_one_overworld_vanilla_flat_theend": "§eProbeer een van: overwereld, vanilla, plat, einde",
-    "iris.bukkit.commandiris.world_staging_completed_restart_server_generate_load": "§aVoorbereiding van de wereld voltooid. Herstart de server om \"{worldName}\" te genereren/laden.",
+    "iris.bukkit.commandiris.world_staging_completed_restarting_server_generate_load": "§aVoorbereiding van de wereld voltooid. Iris herstart de server nu om \"{worldName}\" te genereren/laden.",
     "iris.bukkit.commandiris.exception_raised_during_creation_see_console_more_details": "§cUitzondering bij de schepping.  Zie de console voor meer details.",
     "iris.bukkit.commandiris.successfully_created_your_world": "§aSuccesvol jullie wereld gecreëerd!",
-    "iris.bukkit.commandiris.your_world_will_automatically_be_set_as_main_world_when": "§aUw wereld wordt automatisch ingesteld als de belangrijkste wereld wanneer de server herstart.",
     "iris.bukkit.commandiris.runtime_world_creation_is_disabled_on_folia": "§eRuntime wereld creatie is uitgeschakeld op Folia.",
     "iris.bukkit.commandiris.preparing_world_files_bukkit_yml_next_startup": "§eVoorbereiden van wereldbestanden en bukkit.yml voor volgende opstart...",
     "iris.bukkit.commandiris.failed_stage_world_files_dimension": "§cKon wereldbestanden voor dimensie niet stagen \"{value}\".",
-    "iris.bukkit.commandiris.updated_server_properties_level_name": "§aBijgewerkt server.properties niveau-naam aan \"{name}\".",
-    "iris.bukkit.commandiris.world_was_staged_but_failed_update_server_properties_main_world": "§cWereld werd opgevoerd, maar kon niet bijwerken server.properties De belangrijkste wereld.",
     "iris.bukkit.commandiris.staged_iris_world_with_generator_iris_seed": "§aIris-wereld \"{name}\" voorbereid met generator Iris:{value} en seed {seed}.",
-    "iris.bukkit.commandiris.this_world_is_now_configured_as_main_next_restart": "§aDeze wereld is nu geconfigureerd als hoofd voor volgende herstart.",
     "iris.bukkit.commandiris.failed_update_bukkit_yml": "§cBijwerken is mislukt bukkit.yml: {value}",
     "iris.bukkit.commandiris.specified_player_does_not_exist": "§cDe opgegeven speler bestaat niet.",
     "iris.bukkit.commandiris.iris_v_by_volmit_software": "§aIris /{value} door Volmit Software",
@@ -693,7 +689,6 @@
     "iris.director.commandiris.param.name_world_create": "De naam van de wereld te creëren",
     "iris.director.commandiris.param.dimension_pack_create_world_with": "De dimensie/pack om de wereld te creëren met",
     "iris.director.commandiris.param.seed_generate_world_with": "Het zaad om de wereld te genereren met",
-    "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world": "Of deze wereld automatisch gebruikt moet worden als de belangrijkste wereld",
     "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart": "De exacte bestaande wereldsleuf bij de volgende herstart vervangen",
     "iris.director.commandiris.director.teleport_another_world": "Teleporteren naar een andere wereld",
     "iris.director.commandiris.param.world_teleport": "Wereld te teleporteren naar",

core/src/main/resources/languages/pl_PL.json

@@ -149,17 +149,13 @@
     "iris.bukkit.commandiris.may_we_suggest_name_irisworld_instead_2": "§cCzy możemy zasugerować nazwę \"IrisWorld\"zamiast?",
     "iris.bukkit.commandiris.that_folder_already_exists": "§cTen folder już istnieje!",
     "iris.bukkit.commandiris.try_one_overworld_vanilla_flat_theend": "§eSpróbuj jeden z: zaświaty, vanilla, płaski, koniec",
-    "iris.bukkit.commandiris.world_staging_completed_restart_server_generate_load": "§aPrzygotowanie świata ukończone. Uruchom serwer ponownie, aby wygenerować/wczytać „{worldName}”.",
+    "iris.bukkit.commandiris.world_staging_completed_restarting_server_generate_load": "§aPrzygotowanie świata ukończone. Iris uruchamia teraz serwer ponownie, aby wygenerować/wczytać „{worldName}“.",
     "iris.bukkit.commandiris.exception_raised_during_creation_see_console_more_details": "§cWyjątek podniesiony podczas tworzenia.  Więcej szczegółów znajdziesz w konsoli.",
     "iris.bukkit.commandiris.successfully_created_your_world": "§aZ powodzeniem stworzyłeś swój świat!",
-    "iris.bukkit.commandiris.your_world_will_automatically_be_set_as_main_world_when": "§aTwój świat zostanie automatycznie ustawiony jako główny świat po ponownym uruchomieniu serwera.",
     "iris.bukkit.commandiris.runtime_world_creation_is_disabled_on_folia": "§eRuntime world creation jest wyłączone na Folia.",
     "iris.bukkit.commandiris.preparing_world_files_bukkit_yml_next_startup": "§ePrzygotowanie światowych plików i bukkit.yml dla następnego startup...",
     "iris.bukkit.commandiris.failed_stage_world_files_dimension": "§cNie udało się sscenizować plików świata dla wymiaru \"{value}\".",
-    "iris.bukkit.commandiris.updated_server_properties_level_name": "§aAktualizacja server.properties level- name do \"{name}\".",
-    "iris.bukkit.commandiris.world_was_staged_but_failed_update_server_properties_main_world": "§cŚwiat został wystawiony, ale nie udało się zaktualizować server.properties Główny świat.",
     "iris.bukkit.commandiris.staged_iris_world_with_generator_iris_seed": "§aPrzygotowano świat Iris „{name}” z generatorem Iris:{value} i ziarnem {seed}.",
-    "iris.bukkit.commandiris.this_world_is_now_configured_as_main_next_restart": "§aTen świat jest teraz skonfigurowany jako główny dla następnego restartu.",
     "iris.bukkit.commandiris.failed_update_bukkit_yml": "§cNie udało się zaktualizować bukkit.yml: {value}",
     "iris.bukkit.commandiris.specified_player_does_not_exist": "§cOkreślony gracz nie istnieje.",
     "iris.bukkit.commandiris.iris_v_by_volmit_software": "§aIris v.{value} przez Volmit Software",
@@ -693,7 +689,6 @@
     "iris.director.commandiris.param.name_world_create": "Nazwa świata do stworzenia",
     "iris.director.commandiris.param.dimension_pack_create_world_with": "Wymiar / pakiet do tworzenia świata z",
     "iris.director.commandiris.param.seed_generate_world_with": "Nasienie do generowania świata z",
-    "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world": "Czy automatycznie używać tego świata jako głównego świata",
     "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart": "Zastąp dokładny istniejący slot świata przy następnym restarcie",
     "iris.director.commandiris.director.teleport_another_world": "Teleport do innego świata",
     "iris.director.commandiris.param.world_teleport": "Świat teleportować do",

core/src/main/resources/languages/pt_PT.json

@@ -149,17 +149,13 @@
     "iris.bukkit.commandiris.may_we_suggest_name_irisworld_instead_2": "§cPodemos sugerir o nome \"IrisWorld\" em vez disso?",
     "iris.bukkit.commandiris.that_folder_already_exists": "§cEssa pasta já existe!",
     "iris.bukkit.commandiris.try_one_overworld_vanilla_flat_theend": "§eExperimente um de: overworld, vanilla, flat, theend",
-    "iris.bukkit.commandiris.world_staging_completed_restart_server_generate_load": "§aPreparação do mundo concluída. Reinicie o servidor para gerar/carregar \"{worldName}\".",
+    "iris.bukkit.commandiris.world_staging_completed_restarting_server_generate_load": "§aPreparação do mundo concluída. O Iris está agora a reiniciar o servidor para gerar/carregar \"{worldName}\".",
     "iris.bukkit.commandiris.exception_raised_during_creation_see_console_more_details": "§cExceção levantada durante a criação.  Veja o console para mais detalhes.",
     "iris.bukkit.commandiris.successfully_created_your_world": "§aCriou com sucesso o seu mundo!",
-    "iris.bukkit.commandiris.your_world_will_automatically_be_set_as_main_world_when": "§aSeu mundo será automaticamente definido como o mundo principal quando o servidor reiniciar.",
     "iris.bukkit.commandiris.runtime_world_creation_is_disabled_on_folia": "§eA criação do mundo em execução está desactivada Folia.",
     "iris.bukkit.commandiris.preparing_world_files_bukkit_yml_next_startup": "§ePreparando arquivos mundiais e bukkit.yml para a próxima inicialização...",
     "iris.bukkit.commandiris.failed_stage_world_files_dimension": "§cFalha ao encenar arquivos mundiais para a dimensão \"{value}\".",
-    "iris.bukkit.commandiris.updated_server_properties_level_name": "§aAtualizado server.properties nível-nome para \"{name}\".",
-    "iris.bukkit.commandiris.world_was_staged_but_failed_update_server_properties_main_world": "§cO mundo foi encenado, mas falhou em atualizar server.properties mundo principal.",
     "iris.bukkit.commandiris.staged_iris_world_with_generator_iris_seed": "§aMundo Iris \"{name}\" preparado com o gerador Iris:{value} e a seed {seed}.",
-    "iris.bukkit.commandiris.this_world_is_now_configured_as_main_next_restart": "§aEste mundo está agora configurado como principal para o próximo reinício.",
     "iris.bukkit.commandiris.failed_update_bukkit_yml": "§cFalha ao atualizar bukkit.yml: {value}",
     "iris.bukkit.commandiris.specified_player_does_not_exist": "§cO jogador especificado não existe.",
     "iris.bukkit.commandiris.iris_v_by_volmit_software": "§aÍris v{value} por Volmit Software",
@@ -693,7 +689,6 @@
     "iris.director.commandiris.param.name_world_create": "O nome do mundo para criar",
     "iris.director.commandiris.param.dimension_pack_create_world_with": "A dimensão/pack para criar o mundo com",
     "iris.director.commandiris.param.seed_generate_world_with": "A semente para gerar o mundo com",
-    "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world": "Se deve ou não usar automaticamente este mundo como o mundo principal",
     "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart": "Substituir o espaço exato do mundo existente no próximo reinício",
     "iris.director.commandiris.director.teleport_another_world": "Teletransporte para outro mundo",
     "iris.director.commandiris.param.world_teleport": "Mundo para teletransportar",

core/src/main/resources/languages/ru_RU.json

@@ -149,17 +149,13 @@
     "iris.bukkit.commandiris.may_we_suggest_name_irisworld_instead_2": "§cМожно предложить название \"IrisWorldВместо этого?",
     "iris.bukkit.commandiris.that_folder_already_exists": "§cЭта папка уже существует!",
     "iris.bukkit.commandiris.try_one_overworld_vanilla_flat_theend": "§eПопробуйте один из вариантов: overworld, vanilla, flat, theend",
-    "iris.bukkit.commandiris.world_staging_completed_restart_server_generate_load": "§aПодготовка мира завершена. Перезапустите сервер, чтобы сгенерировать/загрузить «{worldName}».",
+    "iris.bukkit.commandiris.world_staging_completed_restarting_server_generate_load": "§aПодготовка мира завершена. Iris перезапускает сервер, чтобы сгенерировать/загрузить «{worldName}».",
     "iris.bukkit.commandiris.exception_raised_during_creation_see_console_more_details": "§cИсключение, возникшее при сотворении.  Смотрите консоль для более подробной информации.",
     "iris.bukkit.commandiris.successfully_created_your_world": "§aУспешно создал свой мир!",
-    "iris.bukkit.commandiris.your_world_will_automatically_be_set_as_main_world_when": "§aВаш мир будет автоматически установлен в качестве основного мира при перезагрузке сервера.",
     "iris.bukkit.commandiris.runtime_world_creation_is_disabled_on_folia": "Создание мира §eRuntime отключено на Folia.",
     "iris.bukkit.commandiris.preparing_world_files_bukkit_yml_next_startup": "§eПодготовка мировых файлов и bukkit.yml Для следующего стартапа...",
     "iris.bukkit.commandiris.failed_stage_world_files_dimension": "§cНе удалось создать мировые файлы для измерения\".{value}\".",
-    "iris.bukkit.commandiris.updated_server_properties_level_name": "§aОбновлено server.properties имя уровня \"{name}\".",
-    "iris.bukkit.commandiris.world_was_staged_but_failed_update_server_properties_main_world": "§cМир был инсценирован, но не удалось обновить server.properties Главный мир.",
     "iris.bukkit.commandiris.staged_iris_world_with_generator_iris_seed": "§aМир Iris «{name}» подготовлен с генератором Iris:{value} и сидом {seed}.",
-    "iris.bukkit.commandiris.this_world_is_now_configured_as_main_next_restart": "§aЭтот мир теперь настроен как основной для следующего перезапуска.",
     "iris.bukkit.commandiris.failed_update_bukkit_yml": "§cНе удалось обновить bukkit.yml: {value}",
     "iris.bukkit.commandiris.specified_player_does_not_exist": "§cУказанного игрока не существует.",
     "iris.bukkit.commandiris.iris_v_by_volmit_software": "§aИрис v{value} Разработчик Volmit Software",
@@ -693,7 +689,6 @@
     "iris.director.commandiris.param.name_world_create": "Название мира для создания",
     "iris.director.commandiris.param.dimension_pack_create_world_with": "Размер/пакет для создания мира",
     "iris.director.commandiris.param.seed_generate_world_with": "Семя, чтобы создать мир с",
-    "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world": "Использовать или не использовать этот мир как основной",
     "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart": "Заменить точный существующий слот мира при следующем перезапуске",
     "iris.director.commandiris.director.teleport_another_world": "Телепорт в другой мир",
     "iris.director.commandiris.param.world_teleport": "Телепортироваться в мир",

core/src/main/resources/languages/tr_TR.json

@@ -149,17 +149,13 @@
     "iris.bukkit.commandiris.may_we_suggest_name_irisworld_instead_2": "§cAdımı önerebiliriz \"IrisWorldBunun yerine?",
     "iris.bukkit.commandiris.that_folder_already_exists": "§cBu klasör zaten var!",
     "iris.bukkit.commandiris.try_one_overworld_vanilla_flat_theend": "§eBirini deneyin: Overworld, vanilla, düz, son",
-    "iris.bukkit.commandiris.world_staging_completed_restart_server_generate_load": "§aDünya hazırlığı tamamlandı. \"{worldName}\" dünyasını oluşturmak/yüklemek için sunucuyu yeniden başlatın.",
+    "iris.bukkit.commandiris.world_staging_completed_restarting_server_generate_load": "§aDünya hazırlığı tamamlandı. Iris, \"{worldName}\" dünyasını oluşturmak/yüklemek için sunucuyu yeniden başlatıyor.",
     "iris.bukkit.commandiris.exception_raised_during_creation_see_console_more_details": "§cYaratılış sırasında ortaya çıktı.  Konsolu daha fazla ayrıntı için görün.",
     "iris.bukkit.commandiris.successfully_created_your_world": "§aBaşarılı bir şekilde dünyanızı yarattı!",
-    "iris.bukkit.commandiris.your_world_will_automatically_be_set_as_main_world_when": "§aDünyanız otomatik olarak sunucu yeniden başladığında ana dünya olarak belirlenecektir.",
     "iris.bukkit.commandiris.runtime_world_creation_is_disabled_on_folia": "§eRuntime dünya yaratımı engellidir Folia.",
     "iris.bukkit.commandiris.preparing_world_files_bukkit_yml_next_startup": "§eDünya dosyalarını hazırlamak ve bukkit.yml Bir sonraki başlangıç için...",
     "iris.bukkit.commandiris.failed_stage_world_files_dimension": "§cBoyut için dünya dosyalarını sahnelemek için başarısız oldu \"{value}\".",
-    "iris.bukkit.commandiris.updated_server_properties_level_name": "§aGüncelleme Tarihi server.properties Seviye adı \"{name}\".",
-    "iris.bukkit.commandiris.world_was_staged_but_failed_update_server_properties_main_world": "§cDünya sahnelendi, ancak güncellemeyi başaramadı server.properties Ana dünya.",
     "iris.bukkit.commandiris.staged_iris_world_with_generator_iris_seed": "§aIris dünyası \"{name}\", Iris:{value} jeneratörü ve {seed} tohumu ile hazırlandı.",
-    "iris.bukkit.commandiris.this_world_is_now_configured_as_main_next_restart": "§aBu dünya şimdi bir sonraki yeniden başlamak için ana olarak yapılandırılmıştır.",
     "iris.bukkit.commandiris.failed_update_bukkit_yml": "§cgüncellemek için başarısız oldu bukkit.yml: {value}",
     "iris.bukkit.commandiris.specified_player_does_not_exist": "§cBelirtilen oyuncu mevcut değildir.",
     "iris.bukkit.commandiris.iris_v_by_volmit_software": "§aIris{value} Volmit Software",
@@ -693,7 +689,6 @@
     "iris.director.commandiris.param.name_world_create": "Dünyanın adı yaratmak",
     "iris.director.commandiris.param.dimension_pack_create_world_with": "Dünyayı yaratmak için boyut / paket",
     "iris.director.commandiris.param.seed_generate_world_with": "Dünyayı üretmek için tohum",
-    "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world": "Bu dünyayı ana dünya olarak otomatik olarak kullanıp kullanmayalım",
     "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart": "Bir sonraki yeniden başlatmada mevcut tam dünya yuvasını değiştir",
     "iris.director.commandiris.director.teleport_another_world": "Teleport başka bir dünyaya",
     "iris.director.commandiris.param.world_teleport": "Dünya teleport'a",

core/src/main/resources/languages/vi_VI.json

@@ -149,17 +149,13 @@
     "iris.bukkit.commandiris.may_we_suggest_name_irisworld_instead_2": "§cChúng ta có thể đề nghị cái tên \"IrisWorldThay vào đó?",
     "iris.bukkit.commandiris.that_folder_already_exists": "§cThư mục đó đã có!",
     "iris.bukkit.commandiris.try_one_overworld_vanilla_flat_theend": "§eHãy thử một trong những: ngoài thế giới, vanilla, bằng phẳng, kết thúc",
-    "iris.bukkit.commandiris.world_staging_completed_restart_server_generate_load": "§aĐã chuẩn bị xong thế giới. Hãy khởi động lại máy chủ để tạo/tải \"{worldName}\".",
+    "iris.bukkit.commandiris.world_staging_completed_restarting_server_generate_load": "§aĐã chuẩn bị xong thế giới. Iris đang khởi động lại máy chủ để tạo/tải \"{worldName}\".",
     "iris.bukkit.commandiris.exception_raised_during_creation_see_console_more_details": "§cNgoại lệ được nuôi lớn trong suốt quá trình sáng tạo.  Xem bảng điều khiển để biết thêm chi tiết.",
     "iris.bukkit.commandiris.successfully_created_your_world": "§aThành công trong việc tạo ra thế giới của anh!",
-    "iris.bukkit.commandiris.your_world_will_automatically_be_set_as_main_world_when": "§aThế giới của bạn sẽ tự động được thiết lập như thế giới chính khi máy chủ khởi động lại.",
     "iris.bukkit.commandiris.runtime_world_creation_is_disabled_on_folia": "§eComment Folia.",
     "iris.bukkit.commandiris.preparing_world_files_bukkit_yml_next_startup": "§eĐang chuẩn bị tập tin thế giới và bukkit.yml cho lần khởi chạy tiếp theo...",
     "iris.bukkit.commandiris.failed_stage_world_files_dimension": "§cKhông thể tạo tập tin cho chiều không gian{value}\".",
-    "iris.bukkit.commandiris.updated_server_properties_level_name": "§aCập nhật server.properties Cấp-tên là \"{name}\".",
-    "iris.bukkit.commandiris.world_was_staged_but_failed_update_server_properties_main_world": "§cThế giới đã được thiết lập, nhưng không cập nhật được server.properties thế giới chính.",
     "iris.bukkit.commandiris.staged_iris_world_with_generator_iris_seed": "§aĐã chuẩn bị thế giới Iris \"{name}\" với trình tạo Iris:{value} và seed {seed}.",
-    "iris.bukkit.commandiris.this_world_is_now_configured_as_main_next_restart": "§aThế giới này bây giờ được cấu hình là chính cho lần khởi động lại tiếp theo.",
     "iris.bukkit.commandiris.failed_update_bukkit_yml": "§cLỗi cập nhật bukkit.yml: {value}",
     "iris.bukkit.commandiris.specified_player_does_not_exist": "§cNgười chơi đã ghi rõ không tồn tại.",
     "iris.bukkit.commandiris.iris_v_by_volmit_software": "§aIris v.{value} by Volmit Phần mềm",
@@ -693,7 +689,6 @@
     "iris.director.commandiris.param.name_world_create": "Tên của thế giới để tạo ra",
     "iris.director.commandiris.param.dimension_pack_create_world_with": "Kích thước/ lốc tạo ra thế giới với",
     "iris.director.commandiris.param.seed_generate_world_with": "Hạt giống để tạo ra thế giới với",
-    "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world": "Có nên tự động sử dụng thế giới này làm thế giới chính hay không",
     "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart": "Thay thế đúng vị trí thế giới hiện có vào lần khởi động lại tiếp theo",
     "iris.director.commandiris.director.teleport_another_world": "Name",
     "iris.director.commandiris.param.world_teleport": "Thế giới có thể dịch chuyển",

core/src/main/resources/languages/zh_CN.json

@@ -149,17 +149,13 @@
     "iris.bukkit.commandiris.may_we_suggest_name_irisworld_instead_2": "§c建议改用名称 \"IrisWorld\"。",
     "iris.bukkit.commandiris.that_folder_already_exists": "§c该文件夹已存在！",
     "iris.bukkit.commandiris.try_one_overworld_vanilla_flat_theend": "§e可尝试：overworld、vanilla、flat 或 the_end",
-    "iris.bukkit.commandiris.world_staging_completed_restart_server_generate_load": "§a世界暂存完成。请重启服务器以生成并加载 \"{worldName}\"。",
+    "iris.bukkit.commandiris.world_staging_completed_restarting_server_generate_load": "§a世界暂存完成。Iris 正在重启服务器以生成并加载 \"{worldName}\"。",
     "iris.bukkit.commandiris.exception_raised_during_creation_see_console_more_details": "§c创建期间发生异常。详情请查看控制台。",
     "iris.bukkit.commandiris.successfully_created_your_world": "§a世界创建成功！",
-    "iris.bukkit.commandiris.your_world_will_automatically_be_set_as_main_world_when": "§a服务器重启时，此世界将自动设为主世界。",
     "iris.bukkit.commandiris.runtime_world_creation_is_disabled_on_folia": "§eFolia 上已禁用运行时世界创建。",
     "iris.bukkit.commandiris.preparing_world_files_bukkit_yml_next_startup": "§e正在为下次启动准备世界文件和 bukkit.yml...",
     "iris.bukkit.commandiris.failed_stage_world_files_dimension": "§c无法为维度 \"{value}\" 暂存世界文件。",
-    "iris.bukkit.commandiris.updated_server_properties_level_name": "§a已将 server.properties 中的 level-name 更新为 \"{name}\"。",
-    "iris.bukkit.commandiris.world_was_staged_but_failed_update_server_properties_main_world": "§c世界已暂存，但无法更新 server.properties 中的主世界。",
     "iris.bukkit.commandiris.staged_iris_world_with_generator_iris_seed": "§a已暂存 Iris 世界 \"{name}\"，生成器为 Iris:{value}，种子为 {seed}。",
-    "iris.bukkit.commandiris.this_world_is_now_configured_as_main_next_restart": "§a此世界现已设为下次重启后的主世界。",
     "iris.bukkit.commandiris.failed_update_bukkit_yml": "§c无法更新 bukkit.yml：{value}",
     "iris.bukkit.commandiris.specified_player_does_not_exist": "§c指定的玩家不存在。",
     "iris.bukkit.commandiris.iris_v_by_volmit_software": "§aIris v.{value}，由 Volmit Software 开发",
@@ -693,7 +689,6 @@
     "iris.director.commandiris.param.name_world_create": "要创建的世界名称",
     "iris.director.commandiris.param.dimension_pack_create_world_with": "用于创建世界的维度包",
     "iris.director.commandiris.param.seed_generate_world_with": "用于生成世界的种子",
-    "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world": "是否自动将此世界设为主世界",
     "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart": "在下次重启时替换指定的现有世界槽位",
     "iris.director.commandiris.director.teleport_another_world": "传送到另一个世界",
     "iris.director.commandiris.param.world_teleport": "要传送到的世界",

core/src/main/resources/languages/zh_TW.json

@@ -149,17 +149,13 @@
     "iris.bukkit.commandiris.may_we_suggest_name_irisworld_instead_2": "§c建議改用名稱 \"IrisWorld\"。",
     "iris.bukkit.commandiris.that_folder_already_exists": "§c該資料夾已存在！",
     "iris.bukkit.commandiris.try_one_overworld_vanilla_flat_theend": "§e可嘗試：overworld、vanilla、flat 或 the_end",
-    "iris.bukkit.commandiris.world_staging_completed_restart_server_generate_load": "§a世界暫存完成。請重新啟動伺服器以生成並載入 \"{worldName}\"。",
+    "iris.bukkit.commandiris.world_staging_completed_restarting_server_generate_load": "§a世界暫存完成。Iris 正在重新啟動伺服器以生成並載入 \"{worldName}\"。",
     "iris.bukkit.commandiris.exception_raised_during_creation_see_console_more_details": "§c建立期間發生例外。詳細資訊請查看主控台。",
     "iris.bukkit.commandiris.successfully_created_your_world": "§a世界建立成功！",
-    "iris.bukkit.commandiris.your_world_will_automatically_be_set_as_main_world_when": "§a伺服器重新啟動時，此世界將自動設為主世界。",
     "iris.bukkit.commandiris.runtime_world_creation_is_disabled_on_folia": "§eFolia 上已停用執行階段世界建立。",
     "iris.bukkit.commandiris.preparing_world_files_bukkit_yml_next_startup": "§e正在為下次啟動準備世界檔案和 bukkit.yml...",
     "iris.bukkit.commandiris.failed_stage_world_files_dimension": "§c無法為維度 \"{value}\" 暫存世界檔案。",
-    "iris.bukkit.commandiris.updated_server_properties_level_name": "§a已將 server.properties 中的 level-name 更新為 \"{name}\"。",
-    "iris.bukkit.commandiris.world_was_staged_but_failed_update_server_properties_main_world": "§c世界已暫存，但無法更新 server.properties 中的主世界。",
     "iris.bukkit.commandiris.staged_iris_world_with_generator_iris_seed": "§a已暫存 Iris 世界 \"{name}\"，生成器為 Iris:{value}，種子為 {seed}。",
-    "iris.bukkit.commandiris.this_world_is_now_configured_as_main_next_restart": "§a此世界現已設為下次重新啟動後的主世界。",
     "iris.bukkit.commandiris.failed_update_bukkit_yml": "§c無法更新 bukkit.yml：{value}",
     "iris.bukkit.commandiris.specified_player_does_not_exist": "§c指定的玩家不存在。",
     "iris.bukkit.commandiris.iris_v_by_volmit_software": "§aIris v.{value}，由 Volmit Software 開發",
@@ -693,7 +689,6 @@
     "iris.director.commandiris.param.name_world_create": "要建立的世界名稱",
     "iris.director.commandiris.param.dimension_pack_create_world_with": "用於建立世界的維度包",
     "iris.director.commandiris.param.seed_generate_world_with": "用於生成世界的種子",
-    "iris.director.commandiris.param.whether_not_automatically_use_this_world_as_main_world": "是否自動將此世界設為主世界",
     "iris.director.commandiris.param.replace_exact_existing_world_slot_next_restart": "在下次重新啟動時取代指定的現有世界槽位",
     "iris.director.commandiris.director.teleport_another_world": "傳送到另一個世界",
     "iris.director.commandiris.param.world_teleport": "要傳送到的世界",

core/src/test/java/art/arcane/iris/core/ExactWorldSlotPathPolicyTest.java

@@ -9,6 +9,7 @@ import java.nio.file.Path;
 import java.util.List;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertThrows;
 
 public class ExactWorldSlotPathPolicyTest {
@@ -53,6 +54,7 @@ public class ExactWorldSlotPathPolicyTest {
             assertEquals(canonicalRoot, target.levelRoot());
             assertEquals(canonicalRoot.resolve(expectation.relativePath()), target.worldDirectory());
         }
+        assertFalse(Files.exists(canonicalRoot.resolve("dimensions")));
     }
 
     @Test

core/src/test/java/art/arcane/iris/core/IrisDatapackCompilerInputFingerprintTest.java

@@ -1,5 +1,6 @@
 package art.arcane.iris.core;
 
+import art.arcane.iris.core.lifecycle.BukkitWorldConfiguration.IrisGeneratorBinding;
 import org.junit.Assume;
 import org.junit.Rule;
 import org.junit.Test;
@@ -79,6 +80,23 @@ public class IrisDatapackCompilerInputFingerprintTest {
         assertNotEquals(initial, fingerprint(pack, false, "compiler-b"));
     }
 
+    @Test
+    public void configuredLevelStemBindingsSaltTheFingerprint() throws Exception {
+        Path pack = activePack("binding-inputs");
+        IrisGeneratorBinding moon = binding("moon", "overworld");
+        IrisGeneratorBinding mars = binding("mars", "overworld");
+        String empty = fingerprint(pack, List.of(), false, "compiler-a");
+        String moonOnly = fingerprint(pack, List.of(moon), false, "compiler-a");
+        String both = fingerprint(pack, List.of(mars, moon), false, "compiler-a");
+
+        assertNotEquals(empty, moonOnly);
+        assertNotEquals(moonOnly, both);
+        assertEquals(
+                both,
+                fingerprint(pack, List.of(moon, mars), false, "compiler-a")
+        );
+    }
+
     @Test
     public void compilerInputsRejectNestedSymbolicLinks() throws Exception {
         Path pack = activePack("unsafe-input");
@@ -146,6 +164,7 @@ public class IrisDatapackCompilerInputFingerprintTest {
         assertEquals(compilerRoots, compilationRoots);
         assertTrue(!IrisDatapackCompiler.computeInputFingerprint(
                 compilerRoots,
+                List.of(),
                 false,
                 "compiler-a").isBlank());
     }
@@ -163,9 +182,27 @@ public class IrisDatapackCompilerInputFingerprintTest {
     }
 
     private String fingerprint(Path pack, boolean adjustVanillaHeight, String compilerIdentity) throws IOException {
+        return fingerprint(pack, List.of(), adjustVanillaHeight, compilerIdentity);
+    }
+
+    private String fingerprint(
+            Path pack,
+            List<IrisGeneratorBinding> bindings,
+            boolean adjustVanillaHeight,
+            String compilerIdentity
+    ) throws IOException {
         return IrisDatapackCompiler.computeInputFingerprint(
                 List.of(pack.toFile()),
+                bindings,
                 adjustVanillaHeight,
                 compilerIdentity);
     }
+
+    private IrisGeneratorBinding binding(String worldKey, String dimension) {
+        return new IrisGeneratorBinding(
+                "world_iris_" + worldKey,
+                new WorldSlotKey("iris", worldKey),
+                dimension
+        );
+    }
 }

core/src/test/java/art/arcane/iris/core/IrisDatapackCompilerTest.java

@@ -1,5 +1,6 @@
 package art.arcane.iris.core;
 
+import art.arcane.iris.core.lifecycle.BukkitWorldConfiguration.IrisGeneratorBinding;
 import art.arcane.iris.core.nms.datapack.DataVersion;
 import art.arcane.iris.core.nms.datapack.v1217.DataFixerV1217;
 import art.arcane.volmlib.util.collection.KList;
@@ -18,6 +19,7 @@ import java.util.List;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 
 public class IrisDatapackCompilerTest {
@@ -42,6 +44,7 @@ public class IrisDatapackCompilerTest {
         IrisDatapackCompiler.CompilationResult result = IrisDatapackCompiler.compile(
                 packRoots,
                 new KList<File>().qadd(datapackRoot.toFile()),
+                List.of(),
                 new DataFixerV1217(),
                 false
         );
@@ -72,6 +75,7 @@ public class IrisDatapackCompilerTest {
         IrisDatapackCompiler.CompilationResult result = IrisDatapackCompiler.compile(
                 List.of(packRoot.toFile()),
                 new KList<File>().qadd(datapackRoot.toFile()),
+                List.of(),
                 new DataFixerV1217(),
                 false
         );
@@ -106,6 +110,7 @@ public class IrisDatapackCompilerTest {
         IrisDatapackCompiler.compile(
                 List.of(),
                 new KList<File>().qadd(datapackRoot.toFile()),
+                List.of(),
                 new DataFixerV1217(),
                 false
         );
@@ -136,6 +141,7 @@ public class IrisDatapackCompilerTest {
         IrisDatapackCompiler.CompilationResult result = IrisDatapackCompiler.compile(
                 List.of(),
                 new KList<File>().qadd(datapackRoot.toFile()),
+                List.of(),
                 new DataFixerV1217(),
                 false
         );
@@ -147,7 +153,112 @@ public class IrisDatapackCompilerTest {
         assertFalse(Files.exists(stale));
     }
 
+    @Test
+    public void emitsBootNativeCustomLevelStemBinding() throws Exception {
+        Path packRoot = temporaryFolder.newFolder("binding-pack").toPath();
+        Path datapackRoot = temporaryFolder.newFolder("binding-datapack").toPath();
+        createPack(packRoot, "moon_pack", "moon_custom");
+
+        IrisDatapackCompiler.compile(
+                List.of(packRoot.toFile()),
+                new KList<File>().qadd(datapackRoot.toFile()),
+                List.of(binding("moon", "moon_pack")),
+                new DataFixerV1217(),
+                false
+        );
+
+        Path levelStemPath = datapackRoot.resolve("data/iris/dimension/moon.json");
+        JSONObject levelStem = new JSONObject(Files.readString(levelStemPath, StandardCharsets.UTF_8));
+        JSONObject generator = levelStem.getJSONObject("generator");
+        JSONObject settings = generator.getJSONObject("settings");
+        assertEquals("iris:moon_pack", levelStem.getString("type"));
+        assertEquals("minecraft:flat", generator.getString("type"));
+        assertEquals("minecraft:the_void", settings.getString("biome"));
+        assertFalse(settings.getBoolean("features"));
+        assertFalse(settings.getBoolean("lakes"));
+        assertEquals(1, settings.getJSONArray("layers").length());
+        assertEquals(
+                "minecraft:air",
+                settings.getJSONArray("layers").getJSONObject(0).getString("block")
+        );
+        assertEquals(1, settings.getJSONArray("layers").getJSONObject(0).getInt("height"));
+        assertEquals(0, settings.getJSONArray("structure_overrides").length());
+        assertFalse(Files.exists(datapackRoot.resolve("data/minecraft/dimension/overworld.json")));
+        assertFalse(Files.exists(datapackRoot.resolve("data/minecraft/dimension/the_nether.json")));
+        assertFalse(Files.exists(datapackRoot.resolve("data/minecraft/dimension/the_end.json")));
+    }
+
+    @Test
+    public void rejectsBindingToMissingDimension() throws Exception {
+        Path packRoot = temporaryFolder.newFolder("missing-binding-pack").toPath();
+        Path datapackRoot = temporaryFolder.newFolder("missing-binding-datapack").toPath();
+        createPack(packRoot, "available", "available_custom");
+
+        IOException failure = assertThrows(
+                IOException.class,
+                () -> IrisDatapackCompiler.compile(
+                        List.of(packRoot.toFile()),
+                        new KList<File>().qadd(datapackRoot.toFile()),
+                        List.of(binding("moon", "missing")),
+                        new DataFixerV1217(),
+                        false
+                )
+        );
+
+        assertTrue(failure.getMessage().contains("selects missing dimension \"missing\""));
+    }
+
+    @Test
+    public void rejectsBindingToConflictingDuplicateDimension() throws Exception {
+        Path firstPack = temporaryFolder.newFolder("ambiguous-binding-first").toPath();
+        Path secondPack = temporaryFolder.newFolder("ambiguous-binding-second").toPath();
+        Path datapackRoot = temporaryFolder.newFolder("ambiguous-binding-datapack").toPath();
+        createPack(firstPack, "shared", "first_custom", "NORMAL");
+        createPack(secondPack, "shared", "second_custom", "NETHER");
+
+        IOException failure = assertThrows(
+                IOException.class,
+                () -> IrisDatapackCompiler.compile(
+                        List.of(firstPack.toFile(), secondPack.toFile()),
+                        new KList<File>().qadd(datapackRoot.toFile()),
+                        List.of(binding("moon", "shared")),
+                        new DataFixerV1217(),
+                        false
+                )
+        );
+
+        assertTrue(failure.getMessage().contains("selects ambiguous dimension \"shared\""));
+    }
+
+    @Test
+    public void acceptsIdenticalFrozenAndInstalledDimensionDefinitions() throws Exception {
+        Path installedPack = temporaryFolder.newFolder("identical-binding-installed").toPath();
+        Path frozenPack = temporaryFolder.newFolder("identical-binding-frozen").toPath();
+        Path datapackRoot = temporaryFolder.newFolder("identical-binding-datapack").toPath();
+        createPack(installedPack, "shared", "installed_custom");
+        createPack(frozenPack, "shared", "frozen_custom");
+
+        IrisDatapackCompiler.compile(
+                List.of(installedPack.toFile(), frozenPack.toFile()),
+                new KList<File>().qadd(datapackRoot.toFile()),
+                List.of(binding("moon", "shared")),
+                new DataFixerV1217(),
+                false
+        );
+
+        assertTrue(Files.isRegularFile(datapackRoot.resolve("data/iris/dimension/moon.json")));
+    }
+
     private static void createPack(Path root, String dimensionKey, String biomeId) throws Exception {
+        createPack(root, dimensionKey, biomeId, "NORMAL");
+    }
+
+    private static void createPack(
+            Path root,
+            String dimensionKey,
+            String biomeId,
+            String environment
+    ) throws Exception {
         Files.createDirectories(root.resolve("dimensions"));
         Files.createDirectories(root.resolve("biomes"));
         Files.writeString(
@@ -155,14 +266,14 @@ public class IrisDatapackCompilerTest {
                 """
                         {
                           "name": "Test Dimension",
-                          "environment": "NORMAL",
+                          "environment": "%s",
                           "logicalHeight": 256,
                           "dimensionHeight": {
                             "min": -64,
                             "max": 320
                           }
                         }
-                        """,
+                        """.formatted(environment),
                 StandardCharsets.UTF_8
         );
         Files.writeString(
@@ -182,4 +293,12 @@ public class IrisDatapackCompilerTest {
                 StandardCharsets.UTF_8
         );
     }
+
+    private static IrisGeneratorBinding binding(String worldKey, String dimension) {
+        return new IrisGeneratorBinding(
+                "world_iris_" + worldKey,
+                new WorldSlotKey("iris", worldKey),
+                dimension
+        );
+    }
 }

core/src/test/java/art/arcane/iris/core/IrisStartupValidationTest.java

@@ -7,6 +7,7 @@ import java.util.List;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
@@ -86,6 +87,23 @@ public class IrisStartupValidationTest {
         assertEquals("restart boundary", IrisStartupValidation.denialReason().orElseThrow());
     }
 
+    @Test
+    public void restartBoundaryAllowsReplacementStagingWithoutAllowingRuntimeCreation() {
+        IrisStartupValidation.begin();
+        IrisStartupValidation.markDatapacksReady();
+        IrisStartupValidation.markPacksReady();
+        IrisStartupValidation.requireRestart("restart boundary");
+
+        assertThrows(IllegalStateException.class, IrisStartupValidation::requireWorldCreationReady);
+        IrisStartupValidation.requireWorldReplacementStagingReady();
+
+        IrisStartupValidation.markPacksInvalid(List.of("pack validation failed"));
+        assertThrows(
+                IllegalStateException.class,
+                IrisStartupValidation::requireWorldReplacementStagingReady
+        );
+    }
+
     @Test
     public void packValidationInfrastructureFailureDeniesCreation() {
         IrisStartupValidation.begin();

core/src/test/java/art/arcane/iris/core/IrisWorldStorageTest.java

@@ -12,7 +12,9 @@ import java.nio.file.Path;
 import java.util.Properties;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertTrue;
 
 public class IrisWorldStorageTest {
     @Rule
@@ -45,6 +47,113 @@ public class IrisWorldStorageTest {
         assertEquals(new NamespacedKey("iris", "iris_world"), IrisWorldStorage.keyFromName("Iris World", "world"));
     }
 
+    @Test
+    public void mapsPaperStartupNamesWithoutChangingLogicalNames() {
+        NamespacedKey worldKey = new NamespacedKey("iris", "moon");
+
+        assertEquals("world_iris_moon", IrisWorldStorage.configuredWorldName(worldKey, "world"));
+        assertEquals(
+                "world_iris_moon",
+                IrisWorldStorage.configuredWorldName(new WorldSlotKey("iris", "moon"), "world")
+        );
+        assertEquals(worldKey, IrisWorldStorage.keyFromConfiguredWorldName("world_iris_moon", "world"));
+        assertEquals("moon", IrisWorldStorage.logicalName(worldKey, "world"));
+        assertEquals(NamespacedKey.minecraft("overworld"),
+                IrisWorldStorage.keyFromConfiguredWorldName("world", "world"));
+        assertEquals(NamespacedKey.minecraft("the_nether"),
+                IrisWorldStorage.keyFromConfiguredWorldName("world_nether", "world"));
+        assertEquals(NamespacedKey.minecraft("the_end"),
+                IrisWorldStorage.keyFromConfiguredWorldName("world_the_end", "world"));
+    }
+
+    @Test
+    public void configuredWorldNameRejectsUnsafeManagedKeys() {
+        assertThrows(IllegalArgumentException.class,
+                () -> IrisWorldStorage.keyFromConfiguredWorldName("world_iris_nested/world", "world"));
+        assertThrows(IllegalArgumentException.class,
+                () -> IrisWorldStorage.configuredWorldName(new NamespacedKey("other", "moon"), "world"));
+    }
+
+    @Test
+    public void replacementKeyAcceptsExplicitCanonicalIdentities() {
+        assertEquals(
+                NamespacedKey.minecraft("overworld"),
+                IrisWorldStorage.replacementKeyFromName("minecraft:overworld", "world")
+        );
+        assertEquals(
+                NamespacedKey.minecraft("the_nether"),
+                IrisWorldStorage.replacementKeyFromName("MINECRAFT:THE_NETHER", "world")
+        );
+        assertEquals(
+                NamespacedKey.minecraft("the_end"),
+                IrisWorldStorage.replacementKeyFromName("minecraft:the_end", "world")
+        );
+        assertEquals(
+                new NamespacedKey("iris", "moon"),
+                IrisWorldStorage.replacementKeyFromName("iris:moon", "world")
+        );
+        assertEquals(
+                new NamespacedKey("iris", "main"),
+                IrisWorldStorage.replacementKeyFromName("iris:main", "world")
+        );
+        assertEquals(
+                new NamespacedKey("iris", "survival"),
+                IrisWorldStorage.replacementKeyFromName("iris:survival", "survival")
+        );
+        assertEquals(
+                new NamespacedKey("iris", "moon"),
+                IrisWorldStorage.replacementKeyFromName("world_iris_moon", "world")
+        );
+    }
+
+    @Test
+    public void replacementKeyResolvesFriendlyVanillaAliases() {
+        assertEquals(NamespacedKey.minecraft("overworld"),
+                IrisWorldStorage.replacementKeyFromName("main", "world"));
+        assertEquals(NamespacedKey.minecraft("overworld"),
+                IrisWorldStorage.replacementKeyFromName("overworld", "world"));
+        assertEquals(NamespacedKey.minecraft("the_nether"),
+                IrisWorldStorage.replacementKeyFromName("nether", "world"));
+        assertEquals(NamespacedKey.minecraft("the_nether"),
+                IrisWorldStorage.replacementKeyFromName("the_nether", "world"));
+        assertEquals(NamespacedKey.minecraft("the_end"),
+                IrisWorldStorage.replacementKeyFromName("end", "world"));
+        assertEquals(NamespacedKey.minecraft("the_end"),
+                IrisWorldStorage.replacementKeyFromName("the_end", "world"));
+    }
+
+    @Test
+    public void replacementKeyResolvesConfiguredVanillaNamesBeforeFriendlyAliases() {
+        assertEquals(NamespacedKey.minecraft("overworld"),
+                IrisWorldStorage.replacementKeyFromName("survival", "survival"));
+        assertEquals(NamespacedKey.minecraft("the_nether"),
+                IrisWorldStorage.replacementKeyFromName("survival_nether", "survival"));
+        assertEquals(NamespacedKey.minecraft("the_end"),
+                IrisWorldStorage.replacementKeyFromName("survival_the_end", "survival"));
+        assertEquals(NamespacedKey.minecraft("overworld"),
+                IrisWorldStorage.replacementKeyFromName("nether", "nether"));
+    }
+
+    @Test
+    public void replacementKeyMapsOtherBareNamesIntoIrisNamespace() {
+        assertEquals(
+                new NamespacedKey("iris", "moon_base"),
+                IrisWorldStorage.replacementKeyFromName("Moon Base", "world")
+        );
+    }
+
+    @Test
+    public void replacementKeyRejectsUnsafePathsAndInvalidIdentifiers() {
+        assertThrows(IllegalArgumentException.class,
+                () -> IrisWorldStorage.replacementKeyFromName("../world", "world"));
+        assertThrows(IllegalArgumentException.class,
+                () -> IrisWorldStorage.replacementKeyFromName("iris:nested/world", "world"));
+        assertThrows(IllegalArgumentException.class,
+                () -> IrisWorldStorage.replacementKeyFromName("iris:", "world"));
+        assertThrows(IllegalArgumentException.class,
+                () -> IrisWorldStorage.replacementKeyFromName("world", " "));
+    }
+
     @Test
     public void managedKeyRejectsMainWorldsAndUnsafePaths() {
         assertEquals(new NamespacedKey("iris", "iris_world"),
@@ -124,9 +233,26 @@ public class IrisWorldStorageTest {
         Path dimensions = Files.createDirectories(levelRoot.toPath().resolve("dimensions"));
         Path outside = temporaryFolder.newFolder("outside").toPath();
         Files.createSymbolicLink(dimensions.resolve("iris"), outside);
+        NamespacedKey key = new NamespacedKey("iris", "probe");
 
         assertThrows(IllegalArgumentException.class, () -> IrisWorldStorage.requireSafeManagedDimensionRoot(
                 levelRoot,
-                new NamespacedKey("iris", "probe")));
+                key));
+        assertFalse(IrisWorldStorage.isExistingManagedDimensionRoot(levelRoot, key));
+    }
+
+    @Test
+    public void existingManagedDimensionRootRequiresRealDirectory() throws Exception {
+        File levelRoot = temporaryFolder.newFolder("managed-world-admission");
+        Path namespace = Files.createDirectories(levelRoot.toPath().resolve("dimensions/iris"));
+        NamespacedKey missing = new NamespacedKey("iris", "missing");
+        NamespacedKey file = new NamespacedKey("iris", "file");
+        NamespacedKey directory = new NamespacedKey("iris", "directory");
+        Files.writeString(namespace.resolve("file"), "not a directory");
+        Files.createDirectory(namespace.resolve("directory"));
+
+        assertFalse(IrisWorldStorage.isExistingManagedDimensionRoot(levelRoot, missing));
+        assertFalse(IrisWorldStorage.isExistingManagedDimensionRoot(levelRoot, file));
+        assertTrue(IrisWorldStorage.isExistingManagedDimensionRoot(levelRoot, directory));
     }
 }

core/src/test/java/art/arcane/iris/core/IrisWorldsTest.java

@@ -0,0 +1,55 @@
+package art.arcane.iris.core;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Set;
+
+import static org.junit.Assert.assertEquals;
+
+public class IrisWorldsTest {
+    @Rule
+    public TemporaryFolder temporaryFolder = new TemporaryFolder();
+
+    @Test
+    public void registryFileBelongsToSelectedLevelRoot() throws Exception {
+        Path levelRoot = temporaryFolder.newFolder("world").toPath();
+
+        assertEquals(
+                levelRoot.toAbsolutePath().normalize().resolve("iris/worlds.json"),
+                IrisWorlds.registryFile(levelRoot));
+    }
+
+    @Test
+    public void bukkitWorldFilteringUsesExactStorageInSelectedRoot() throws Exception {
+        Path selectedRoot = temporaryFolder.newFolder("world").toPath();
+        Path otherRoot = temporaryFolder.newFolder("archive").toPath();
+        Files.createDirectories(selectedRoot.resolve("dimensions/minecraft/overworld"));
+        Files.createDirectories(selectedRoot.resolve("dimensions/iris/moon"));
+        Files.createDirectories(otherRoot.resolve("dimensions/iris/foreign"));
+        Files.createDirectories(selectedRoot.resolve("dimensions/iris"));
+        Files.writeString(selectedRoot.resolve("dimensions/iris/not_a_directory"), "not storage");
+
+        Map<String, String> configuredWorlds = new LinkedHashMap<>();
+        configuredWorlds.put("world", "overworld");
+        configuredWorlds.put("world_nether", "underworld");
+        configuredWorlds.put("world_iris_moon", "overworld");
+        configuredWorlds.put("moon", "overworld");
+        configuredWorlds.put("world_iris_foreign", "overworld");
+        configuredWorlds.put("archive_iris_foreign", "overworld");
+        configuredWorlds.put("foreign", "overworld");
+        configuredWorlds.put("world_iris_not_a_directory", "overworld");
+        configuredWorlds.put("world_iris_missing", "overworld");
+
+        Map<String, String> selected = IrisWorlds.filterBukkitWorldsByStorage(selectedRoot, configuredWorlds);
+        Map<String, String> other = IrisWorlds.filterBukkitWorldsByStorage(otherRoot, configuredWorlds);
+
+        assertEquals(Set.of("world", "world_iris_moon"), selected.keySet());
+        assertEquals(Set.of("archive_iris_foreign"), other.keySet());
+    }
+}

core/src/test/java/art/arcane/iris/core/lifecycle/BukkitWorldConfigurationTest.java

@@ -1,5 +1,6 @@
 package art.arcane.iris.core.lifecycle;
 
+import art.arcane.iris.core.WorldSlotKey;
 import org.bukkit.configuration.file.YamlConfiguration;
 import org.junit.Rule;
 import org.junit.Test;
@@ -13,6 +14,7 @@ import java.nio.channels.ServerSocketChannel;
 import java.nio.file.FileSystems;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.List;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
@@ -26,6 +28,112 @@ public class BukkitWorldConfigurationTest {
     @Rule
     public TemporaryFolder temporaryFolder = new TemporaryFolder();
 
+    @Test
+    public void readsOnlyCanonicalCustomIrisGeneratorBindings() throws Exception {
+        File configuration = temporaryFolder.newFile("binding-bukkit.yml");
+        Path levelRoot = temporaryFolder.newFolder("binding-level-root").toPath();
+        Files.createDirectories(levelRoot.resolve("dimensions/iris/moon"));
+        YamlConfiguration yaml = new YamlConfiguration();
+        yaml.set("worlds.world.generator", "Iris:overworld");
+        yaml.set("worlds.world_nether.generator", "Iris:underworld");
+        yaml.set("worlds.world_the_end.generator", "Iris:theend");
+        yaml.set("worlds.moon.generator", "Iris:noncanonical_short_name");
+        yaml.set("worlds.world_iris_moon.generator", "Iris:moon_pack");
+        yaml.set("worlds.world_iris_other.generator", "Other:generator");
+        yaml.save(configuration);
+
+        List<BukkitWorldConfiguration.IrisGeneratorBinding> bindings =
+                BukkitWorldConfiguration.readIrisGeneratorBindings(configuration, "world", levelRoot);
+
+        assertEquals(List.of(new BukkitWorldConfiguration.IrisGeneratorBinding(
+                "world_iris_moon",
+                new WorldSlotKey("iris", "moon"),
+                "moon_pack"
+        )), bindings);
+    }
+
+    @Test
+    public void rejectsCustomIrisBindingWithoutSelectedDimension() throws Exception {
+        File configuration = temporaryFolder.newFile("missing-binding-dimension.yml");
+        Path levelRoot = temporaryFolder.newFolder("missing-binding-level-root").toPath();
+        Files.createDirectories(levelRoot.resolve("dimensions/iris/moon"));
+        YamlConfiguration yaml = new YamlConfiguration();
+        yaml.set("worlds.world_iris_moon.generator", "Iris");
+        yaml.save(configuration);
+
+        IOException failure = assertThrows(
+                IOException.class,
+                () -> BukkitWorldConfiguration.readIrisGeneratorBindings(configuration, "world", levelRoot)
+        );
+
+        assertTrue(failure.getMessage().contains("must select a dimension"));
+    }
+
+    @Test
+    public void ignoresNoncanonicalShortNamesThatCollapseOntoCanonicalIrisKeys() throws Exception {
+        File configuration = temporaryFolder.newFile("ambiguous-binding-name.yml");
+        Path levelRoot = temporaryFolder.newFolder("ambiguous-binding-level-root").toPath();
+        Files.createDirectories(levelRoot.resolve("dimensions/iris/moon"));
+        YamlConfiguration yaml = new YamlConfiguration();
+        yaml.set("worlds.moon.generator", "Iris:moon_pack");
+        yaml.set("worlds.world_iris_moon.generator", "Iris:moon_pack");
+        yaml.save(configuration);
+
+        assertEquals(List.of(new BukkitWorldConfiguration.IrisGeneratorBinding(
+                "world_iris_moon",
+                new WorldSlotKey("iris", "moon"),
+                "moon_pack"
+        )), BukkitWorldConfiguration.readIrisGeneratorBindings(configuration, "world", levelRoot));
+    }
+
+    @Test
+    public void admitsOnlyExistingCustomWorldDirectoriesUnderSelectedLevelRoot() throws Exception {
+        File configuration = temporaryFolder.newFile("root-admission-bukkit.yml");
+        Path selectedRoot = temporaryFolder.newFolder("selected-level-root").toPath();
+        Path otherRoot = temporaryFolder.newFolder("other-level-root").toPath();
+        Files.createDirectories(selectedRoot.resolve("dimensions/iris/moon"));
+        Files.createDirectories(otherRoot.resolve("dimensions/iris/moon"));
+        Files.createDirectories(selectedRoot.resolve("dimensions/iris"));
+        Files.writeString(selectedRoot.resolve("dimensions/iris/file"), "not a world directory");
+        YamlConfiguration yaml = new YamlConfiguration();
+        yaml.set("worlds.world_iris_moon.generator", "Iris:moon_pack");
+        yaml.set("worlds.other_iris_moon.generator", "Iris:other_pack");
+        yaml.set("worlds.world_iris_missing.generator", "Iris:missing_pack");
+        yaml.set("worlds.world_iris_file.generator", "Iris:file_pack");
+        yaml.save(configuration);
+
+        List<BukkitWorldConfiguration.IrisGeneratorBinding> bindings =
+                BukkitWorldConfiguration.readIrisGeneratorBindings(configuration, "world", selectedRoot);
+
+        assertEquals(List.of(new BukkitWorldConfiguration.IrisGeneratorBinding(
+                "world_iris_moon",
+                new WorldSlotKey("iris", "moon"),
+                "moon_pack"
+        )), bindings);
+    }
+
+    @Test
+    public void excludesSymlinkedCustomWorldTarget() throws Exception {
+        File configuration = temporaryFolder.newFile("symlink-admission-bukkit.yml");
+        Path levelRoot = temporaryFolder.newFolder("symlink-level-root").toPath();
+        Path namespaceRoot = Files.createDirectories(levelRoot.resolve("dimensions/iris"));
+        Path outside = temporaryFolder.newFolder("symlink-world-outside").toPath();
+        try {
+            Files.createSymbolicLink(namespaceRoot.resolve("moon"), outside);
+        } catch (IOException | UnsupportedOperationException | SecurityException exception) {
+            assumeNoException(exception);
+        }
+        YamlConfiguration yaml = new YamlConfiguration();
+        yaml.set("worlds.world_iris_moon.generator", "Iris:moon_pack");
+        yaml.save(configuration);
+
+        assertTrue(BukkitWorldConfiguration.readIrisGeneratorBindings(
+                configuration,
+                "world",
+                levelRoot
+        ).isEmpty());
+    }
+
     @Test
     public void registersAndRemovesWorldAtomically() throws Exception {
         File configuration = temporaryFolder.newFile("bukkit.yml");

core/src/test/java/art/arcane/iris/core/lifecycle/IrisWorldRemovalServiceTest.java

@@ -1,6 +1,7 @@
 package art.arcane.iris.core.lifecycle;
 
 import art.arcane.iris.core.WorldRemovalPathPolicy;
+import org.bukkit.configuration.file.YamlConfiguration;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
@@ -18,6 +19,7 @@ import java.util.function.BooleanSupplier;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertSame;
 import static org.junit.Assert.assertTrue;
 
@@ -112,6 +114,34 @@ public class IrisWorldRemovalServiceTest {
         assertTrue(result.registryChanged());
     }
 
+    @Test
+    public void bukkitUnregistrationUsesCanonicalPaperStartupName() throws Exception {
+        Path levelRoot = temporaryFolder.newFolder("world").toPath();
+        WorldRemovalPathPolicy.Target target = WorldRemovalPathPolicy.resolve("moon", "world", levelRoot);
+
+        assertEquals(
+                "world_iris_moon",
+                IrisWorldRemovalService.bukkitConfigurationWorldName(target)
+        );
+    }
+
+    @Test
+    public void diskInspectionReadsOnlyCanonicalPaperStartupSection() throws Exception {
+        Path levelRoot = temporaryFolder.newFolder("inspection-world").toPath();
+        WorldRemovalPathPolicy.Target target = WorldRemovalPathPolicy.resolve(
+                "moon",
+                "inspection-world",
+                levelRoot
+        );
+        YamlConfiguration configuration = new YamlConfiguration();
+        configuration.set("worlds.moon.generator", "Iris:noncanonical");
+
+        assertNull(IrisWorldRemovalService.bukkitGenerator(configuration, target));
+
+        configuration.set("worlds.inspection-world_iris_moon.generator", "Iris:overworld");
+        assertEquals("Iris:overworld", IrisWorldRemovalService.bukkitGenerator(configuration, target));
+    }
+
     @Test
     public void registryFailureStopsBeforeFilesystemDeletion() throws Exception {
         LifecycleOperationCoordinator coordinator = new LifecycleOperationCoordinator();

core/src/test/java/art/arcane/iris/core/lifecycle/WorldReplacementBootstrapTest.java

@@ -238,6 +238,57 @@ public class WorldReplacementBootstrapTest {
         assertFalse(Files.exists(paths(first).backup()));
     }
 
+    @Test
+    public void publishesTwoDistinctArmedReplacementsInOneColdReconcile() throws Exception {
+        Transaction nether = stagedTransaction(Phase.ARMED, true, "nether-original");
+        configureReplacement(nether);
+
+        WorldSlotKey endKey = WorldSlotKey.minecraft("the_end");
+        ExactWorldSlotPathPolicy.Target endTarget = ExactWorldSlotPathPolicy.resolve(levelRoot, endKey);
+        WorldGeneratorSnapshot endOriginal = BukkitWorldConfiguration.snapshot(
+                bukkitConfiguration.toFile(),
+                "world_the_end"
+        );
+        UUID endId = UUID.randomUUID();
+        ReplacementPaths endPaths = WorldReplacementFilesystem.paths(endTarget, endId);
+        writeOriginalTarget(endPaths, "end-original");
+        Path endDimension = endPaths.stage().resolve("iris/pack/dimensions/theend.json");
+        Files.createDirectories(endDimension.getParent());
+        Files.writeString(endDimension, "end-replacement");
+        String endFingerprint = WorldReplacementFilesystem.fingerprintPack(
+                endPaths.stage().resolve("iris/pack")
+        );
+        Transaction end = new Transaction(
+                endId,
+                endKey,
+                "world_the_end",
+                endTarget.levelRoot(),
+                "theend",
+                SEED,
+                endFingerprint,
+                endOriginal,
+                true,
+                Phase.ARMED
+        );
+        WorldReplacementJournal.write(dataDirectory, end);
+        configureReplacement(end);
+
+        WorldReplacementBootstrap.ReconcileResult result = reconcile();
+
+        assertEquals(2, result.transactions());
+        assertEquals(2, result.published());
+        assertEquals(0, result.rolledBack());
+        assertEquals(0, result.retained());
+        assertEquals("replacement", replacementContent(target.worldDirectory()));
+        assertEquals("end-replacement", Files.readString(endTarget.worldDirectory()
+                .resolve("iris/pack/dimensions/theend.json")));
+        assertEquals("nether-original", Files.readString(backup(nether).resolve("original.txt")));
+        assertEquals("end-original", Files.readString(endPaths.backup().resolve("original.txt")));
+        List<Transaction> published = WorldReplacementJournal.load(dataDirectory, levelRoot);
+        assertEquals(2, published.size());
+        assertTrue(published.stream().allMatch(transaction -> transaction.phase() == Phase.PUBLISHED));
+    }
+
     @Test
     public void roundTripsBlankAndWhitespaceOriginalGenerators() throws Exception {
         for (String generator : List.of("", "   ")) {
@@ -260,24 +311,15 @@ public class WorldReplacementBootstrapTest {
     }
 
     @Test
-    public void rejectsIrisWorldKeysThatCollideWithConfiguredVanillaAliases() {
-        WorldGeneratorSnapshot original = new WorldGeneratorSnapshot(false, false, false, null, false, null);
-        for (String alias : List.of("world", "world_nether", "world_the_end")) {
-            Transaction transaction = new Transaction(
-                    UUID.randomUUID(),
-                    new WorldSlotKey("iris", alias),
-                    alias,
-                    levelRoot,
-                    "underworld",
-                    SEED,
-                    "0".repeat(64),
-                    original,
-                    false,
-                    Phase.ARMED
+    public void usesPaperStartupAliasesForIrisReplacementJournals() {
+        assertEquals(
+                "world_iris_moon",
+                WorldReplacementJournal.logicalWorldName(levelRoot, new WorldSlotKey("iris", "moon"))
+        );
+        assertEquals(
+                "world_iris_world_nether",
+                WorldReplacementJournal.logicalWorldName(levelRoot, new WorldSlotKey("iris", "world_nether"))
         );
-
-            assertThrows(IOException.class, () -> WorldReplacementJournal.resolveTarget(transaction, levelRoot));
-        }
     }
 
     @Test

core/src/test/java/art/arcane/iris/core/lifecycle/WorldReplacementFilesystemTest.java

@@ -17,6 +17,7 @@ import java.util.stream.Stream;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 
@@ -67,7 +68,10 @@ public class WorldReplacementFilesystemTest {
                 () -> WorldReplacementFilesystem.requireExistingTarget(paths)
         );
 
-        assertTrue(failure.getMessage().contains("requires an existing exact world slot"));
+        assertEquals(
+                "/iris replace requires an existing exact world slot; use /iris create for a new world.",
+                failure.getMessage()
+        );
         assertFalse(Files.exists(paths.target()));
         assertFalse(Files.exists(paths.stage()));
         assertFalse(Files.exists(paths.backup()));
@@ -92,7 +96,7 @@ public class WorldReplacementFilesystemTest {
     }
 
     @Test
-    public void rejectsUnmigratedRetainedWorldBeforePublication() throws Exception {
+    public void rejectsIncompleteCurrentPaperWorldBeforePublication() throws Exception {
         WorldReplacementFilesystem.ReplacementPaths paths = paths("missing-paper-metadata", TRANSACTION_ID);
         Files.createDirectories(paths.target());
         Files.writeString(paths.target().resolve("original.txt"), "original");
@@ -109,7 +113,7 @@ public class WorldReplacementFilesystemTest {
     }
 
     @Test
-    public void rejectsUnmigratedRetainedWorldAtAdmission() throws Exception {
+    public void rejectsIncompleteCurrentPaperWorldAtAdmission() throws Exception {
         WorldReplacementFilesystem.ReplacementPaths paths = paths("admit-missing-paper-metadata", TRANSACTION_ID);
         Files.createDirectories(paths.target());
         Files.writeString(paths.target().resolve("original.txt"), "original");
@@ -331,6 +335,38 @@ public class WorldReplacementFilesystemTest {
         );
     }
 
+    @Test
+    public void ignoresGeneratedAuthoringMetadataWithoutIgnoringNestedPackContent() throws Exception {
+        Path pack = temporaryFolder.newFolder("generated-metadata").toPath();
+        Path objects = Files.createDirectories(pack.resolve("objects"));
+        Files.writeString(objects.resolve("tree.iob"), "tree");
+        String expected = WorldReplacementFilesystem.fingerprintPack(pack);
+
+        Files.createDirectories(pack.resolve(".iris/schema"));
+        Files.writeString(pack.resolve(".iris/schema/dimensions-schema.json"), "schema");
+        Files.createDirectories(pack.resolve(".idea"));
+        Files.writeString(pack.resolve(".idea/jsonSchemas.xml"), "generated UUIDs");
+        Files.writeString(pack.resolve("pack.code-workspace"), "workspace");
+        Files.writeString(objects.resolve("editor.code-workspace"), "nested workspace");
+
+        assertEquals(expected, WorldReplacementFilesystem.fingerprintPack(pack));
+
+        Path nestedPackContent = Files.createDirectories(objects.resolve(".iris"));
+        Files.writeString(nestedPackContent.resolve("semantic.json"), "pack content");
+
+        assertNotEquals(expected, WorldReplacementFilesystem.fingerprintPack(pack));
+    }
+
+    @Test
+    public void validatesExcludedAuthoringMetadataForUnsafeEntries() throws Exception {
+        Path pack = temporaryFolder.newFolder("unsafe-generated-metadata").toPath();
+        Path metadata = Files.createDirectories(pack.resolve(".iris"));
+        Path outside = temporaryFolder.newFile("outside-generated-metadata.txt").toPath();
+        Files.createSymbolicLink(metadata.resolve("linked.json"), outside);
+
+        assertThrows(IOException.class, () -> WorldReplacementFilesystem.fingerprintPack(pack));
+    }
+
     @Test
     public void rejectsMalformedAndCrossTransactionPaths() throws Exception {
         Path parent = temporaryFolder.newFolder("invalid-paths").toPath();

core/src/test/java/art/arcane/iris/core/lifecycle/WorldReplacementSeedTest.java

@@ -0,0 +1,143 @@
+package art.arcane.iris.core.lifecycle;
+
+import art.arcane.volmlib.util.nbt.io.NBTUtil;
+import art.arcane.volmlib.util.nbt.io.NamedTag;
+import art.arcane.volmlib.util.nbt.tag.CompoundTag;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertTrue;
+
+public class WorldReplacementSeedTest {
+    private static final long SEED = -734829104958217364L;
+
+    @Rule
+    public TemporaryFolder temporaryFolder = new TemporaryFolder();
+
+    @Test
+    public void readsAuthoritativeLongSeed() throws Exception {
+        CompoundTag data = new CompoundTag();
+        data.putLong("seed", SEED);
+        CompoundTag root = new CompoundTag();
+        root.put("data", data);
+        Path worldDirectory = writeSettings("valid", root);
+
+        assertEquals(SEED, WorldReplacementSeed.readAuthoritativeSeed(worldDirectory));
+    }
+
+    @Test
+    public void copiesSettingsAndRewritesOnlyAuthoritativeSeed() throws Exception {
+        CompoundTag dimensions = new CompoundTag();
+        dimensions.putString("marker", "preserved");
+        CompoundTag data = new CompoundTag();
+        data.putLong("seed", 1337L);
+        data.putString("generator", "preserved");
+        data.put("dimensions", dimensions);
+        CompoundTag root = new CompoundTag();
+        root.put("data", data);
+        root.putString("root-marker", "preserved");
+        Path sourceWorld = writeSettings("copy-source", root);
+        Path targetWorld = temporaryFolder.newFolder("copy-target").toPath();
+
+        WorldReplacementSeed.copyWithAuthoritativeSeed(sourceWorld, targetWorld, SEED);
+
+        assertEquals(1337L, WorldReplacementSeed.readAuthoritativeSeed(sourceWorld));
+        assertEquals(SEED, WorldReplacementSeed.readAuthoritativeSeed(targetWorld));
+        NamedTag copied = NBTUtil.read(settingsPath(targetWorld).toFile());
+        CompoundTag copiedRoot = (CompoundTag) copied.getTag();
+        CompoundTag copiedData = copiedRoot.getCompoundTag("data");
+        assertEquals("preserved", copiedRoot.getString("root-marker"));
+        assertEquals("preserved", copiedData.getString("generator"));
+        assertEquals("preserved", copiedData.getCompoundTag("dimensions").getString("marker"));
+    }
+
+    @Test
+    public void rejectsMissingDataCompound() throws Exception {
+        Path worldDirectory = writeSettings("missing-data", new CompoundTag());
+
+        IOException failure = assertThrows(
+                IOException.class,
+                () -> WorldReplacementSeed.readAuthoritativeSeed(worldDirectory)
+        );
+
+        assertTrue(failure.getMessage().contains("missing data"));
+    }
+
+    @Test
+    public void rejectsMissingSeed() throws Exception {
+        CompoundTag root = new CompoundTag();
+        root.put("data", new CompoundTag());
+        Path worldDirectory = writeSettings("missing-seed", root);
+
+        IOException failure = assertThrows(
+                IOException.class,
+                () -> WorldReplacementSeed.readAuthoritativeSeed(worldDirectory)
+        );
+
+        assertTrue(failure.getMessage().contains("missing data.seed"));
+    }
+
+    @Test
+    public void rejectsWrongDataType() throws Exception {
+        CompoundTag root = new CompoundTag();
+        root.putString("data", "invalid");
+        Path worldDirectory = writeSettings("wrong-data-type", root);
+
+        IOException failure = assertThrows(
+                IOException.class,
+                () -> WorldReplacementSeed.readAuthoritativeSeed(worldDirectory)
+        );
+
+        assertTrue(failure.getMessage().contains("data must be a compound tag"));
+    }
+
+    @Test
+    public void rejectsNonLongSeed() throws Exception {
+        CompoundTag data = new CompoundTag();
+        data.putInt("seed", 1337);
+        CompoundTag root = new CompoundTag();
+        root.put("data", data);
+        Path worldDirectory = writeSettings("wrong-seed-type", root);
+
+        IOException failure = assertThrows(
+                IOException.class,
+                () -> WorldReplacementSeed.readAuthoritativeSeed(worldDirectory)
+        );
+
+        assertTrue(failure.getMessage().contains("data.seed must be a long tag"));
+    }
+
+    @Test
+    public void rejectsCorruptSettings() throws Exception {
+        Path worldDirectory = temporaryFolder.newFolder("corrupt").toPath();
+        Path settings = settingsPath(worldDirectory);
+        Files.createDirectories(settings.getParent());
+        Files.write(settings, new byte[]{10, 0});
+
+        IOException failure = assertThrows(
+                IOException.class,
+                () -> WorldReplacementSeed.readAuthoritativeSeed(worldDirectory)
+        );
+
+        assertTrue(failure.getMessage().contains("Could not read Paper world generation settings"));
+    }
+
+    private Path writeSettings(String name, CompoundTag root) throws Exception {
+        Path worldDirectory = temporaryFolder.newFolder(name).toPath();
+        Path settings = settingsPath(worldDirectory);
+        Files.createDirectories(settings.getParent());
+        NBTUtil.write(root, settings.toFile());
+        return worldDirectory;
+    }
+
+    private Path settingsPath(Path worldDirectory) {
+        return worldDirectory.resolve("data/minecraft/world_gen_settings.dat");
+    }
+}

core/src/test/java/art/arcane/iris/core/pack/AtomicDirectoryPublisherTest.java

@@ -5,11 +5,13 @@ import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
 
 import java.nio.file.Files;
+import java.nio.file.FileAlreadyExistsException;
 import java.nio.file.Path;
 import java.util.stream.Stream;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 
 public class AtomicDirectoryPublisherTest {
@@ -52,4 +54,21 @@ public class AtomicDirectoryPublisherTest {
         assertTrue(Files.isDirectory(target));
         assertEquals("old", Files.readString(target.resolve("value.txt")));
     }
+
+    @Test
+    public void absentPublicationRefusesAnExistingTargetWithoutMovingEitherDirectory() throws Exception {
+        Path root = temporaryFolder.getRoot().toPath();
+        Path target = Files.createDirectory(root.resolve("existing-target"));
+        Files.writeString(target.resolve("value.txt"), "old");
+        Path staged = Files.createDirectory(root.resolve("absent-stage"));
+        Files.writeString(staged.resolve("value.txt"), "new");
+
+        assertThrows(
+                FileAlreadyExistsException.class,
+                () -> AtomicDirectoryPublisher.publishAbsent(staged, target)
+        );
+
+        assertEquals("old", Files.readString(target.resolve("value.txt")));
+        assertEquals("new", Files.readString(staged.resolve("value.txt")));
+    }
 }

core/src/test/java/art/arcane/iris/core/pack/DefaultPackBootstrapProvisionerTest.java

@@ -1,5 +1,6 @@
 package art.arcane.iris.core.pack;
 
+import art.arcane.iris.core.lifecycle.BukkitStartupPaths;
 import com.sun.net.httpserver.HttpExchange;
 import com.sun.net.httpserver.HttpServer;
 import org.junit.Assume;
@@ -49,6 +50,7 @@ public class DefaultPackBootstrapProvisionerTest {
         try {
             Path dataDirectory = root.resolve("plugins/Iris");
             DefaultPackBootstrapProvisioner.ProvisionOptions options = new DefaultPackBootstrapProvisioner.ProvisionOptions(
+                    List.of(),
                     List.of(),
                     HttpClient.newBuilder().connectTimeout(Duration.ofSeconds(2)).build(),
                     Clock.fixed(Instant.parse("2026-07-12T12:00:00Z"), ZoneOffset.UTC),
@@ -71,7 +73,12 @@ public class DefaultPackBootstrapProvisionerTest {
             assertTrue(result.packRoots().isEmpty());
             assertEquals(0, requests.get());
             assertTrue(Files.isRegularFile(result.datapackRoot().resolve("pack.mcmeta")));
-            assertTrue(DefaultPackBootstrapProvisioner.isProvisioned(dataDirectory, root, List.of()));
+            assertTrue(DefaultPackBootstrapProvisioner.isProvisioned(
+                    dataDirectory,
+                    root,
+                    List.of(),
+                    List.of()
+            ));
         } finally {
             server.stop(0);
             delete(root);
@@ -114,14 +121,24 @@ public class DefaultPackBootstrapProvisionerTest {
             assertTrue(Files.isRegularFile(installed.datapackRoot().resolve("data/overworld/worldgen/biome/bootstrap_biome.json")));
             assertTrue(Files.isRegularFile(installed.datapackRoot().resolve("data/underworld/worldgen/biome/underworld_biome.json")));
             assertFalse(Files.exists(dataDirectory.resolve("bootstrap/datapack")));
-            assertTrue(DefaultPackBootstrapProvisioner.isProvisioned(dataDirectory, root, options.packs()));
+            assertTrue(DefaultPackBootstrapProvisioner.isProvisioned(
+                    dataDirectory,
+                    root,
+                    options.packs(),
+                    options.bindings()
+            ));
             assertTrue(DefaultPackBootstrapProvisioner.wasProvisionedThisStartup());
             Properties marker = loadProperties(dataDirectory.resolve("bootstrap/provisioned.properties"));
             assertEquals("true", marker.getProperty("pack.overworld.managed"));
             assertEquals("true", marker.getProperty("pack.underworld.managed"));
             assertEquals("underworld", marker.getProperty("pack.underworld.requiredDimension"));
             delete(installed.packRoots().get("underworld"));
-            assertFalse(DefaultPackBootstrapProvisioner.isProvisioned(dataDirectory, root, options.packs()));
+            assertFalse(DefaultPackBootstrapProvisioner.isProvisioned(
+                    dataDirectory,
+                    root,
+                    options.packs(),
+                    options.bindings()
+            ));
         } finally {
             server.stop(0);
             delete(root);
@@ -309,7 +326,12 @@ public class DefaultPackBootstrapProvisionerTest {
             assertTrue(Files.isRegularFile(result.datapackRoot().resolve("data/overworld/worldgen/biome/local_biome.json")));
 
             Files.writeString(target.resolve("biomes/local.json"), biomeJson("changed_biome"), StandardCharsets.UTF_8);
-            assertFalse(DefaultPackBootstrapProvisioner.isProvisioned(dataDirectory, root, options.packs()));
+            assertFalse(DefaultPackBootstrapProvisioner.isProvisioned(
+                    dataDirectory,
+                    root,
+                    options.packs(),
+                    options.bindings()
+            ));
             DefaultPackBootstrapProvisioner.ProvisionResult updated = DefaultPackBootstrapProvisioner.provision(
                     dataDirectory,
                     ignored -> {
@@ -338,7 +360,12 @@ public class DefaultPackBootstrapProvisionerTest {
             writePack(dataDirectory.resolve("packs/second"), "second", "second_biome");
             writePack(root.resolve("dimensions/example/world/iris/pack"), "world_local", "world_local_biome");
 
-            assertFalse(DefaultPackBootstrapProvisioner.isProvisioned(dataDirectory, root, options.packs()));
+            assertFalse(DefaultPackBootstrapProvisioner.isProvisioned(
+                    dataDirectory,
+                    root,
+                    options.packs(),
+                    options.bindings()
+            ));
             DefaultPackBootstrapProvisioner.ProvisionResult updated = DefaultPackBootstrapProvisioner.provision(
                     dataDirectory,
                     ignored -> {
@@ -591,6 +618,56 @@ public class DefaultPackBootstrapProvisionerTest {
         }
     }
 
+    @Test
+    public void effectiveStartupBindingsInstallAndRefreshBootNativeLevelStem() throws Exception {
+        Path serverRoot = Files.createTempDirectory("iris-bootstrap-level-stem");
+        try {
+            Path dataDirectory = serverRoot.resolve("plugins/Iris");
+            Path levelRoot = serverRoot.resolve("levels/primary");
+            Path packRoot = levelRoot.resolve("dimensions/iris/moon/iris/pack");
+            Files.createDirectories(levelRoot);
+            Files.writeString(
+                    serverRoot.resolve("server.properties"),
+                    "level-name=levels/primary\n",
+                    StandardCharsets.UTF_8
+            );
+            writePack(packRoot, "overworld", "overworld_biome");
+            Files.writeString(
+                    packRoot.resolve("dimensions/underworld.json"),
+                    dimensionJson("underworld"),
+                    StandardCharsets.UTF_8
+            );
+            Files.writeString(
+                    serverRoot.resolve("bukkit.yml"),
+                    "worlds:\n  primary_iris_moon:\n    generator: Iris:overworld\n",
+                    StandardCharsets.UTF_8
+            );
+            BukkitStartupPaths startupPaths = BukkitStartupPaths.resolve(serverRoot, new String[0]);
+
+            DefaultPackBootstrapProvisioner.ProvisionResult installed =
+                    DefaultPackBootstrapProvisioner.provision(dataDirectory, ignored -> {
+                    }, startupPaths);
+
+            Path levelStem = installed.datapackRoot().resolve("data/iris/dimension/moon.json");
+            assertEquals(DefaultPackBootstrapProvisioner.ProvisionStatus.INSTALLED, installed.status());
+            assertTrue(Files.readString(levelStem).contains("\"type\": \"iris:overworld\""));
+
+            Files.writeString(
+                    serverRoot.resolve("bukkit.yml"),
+                    "worlds:\n  primary_iris_moon:\n    generator: Iris:underworld\n",
+                    StandardCharsets.UTF_8
+            );
+            DefaultPackBootstrapProvisioner.ProvisionResult updated =
+                    DefaultPackBootstrapProvisioner.provision(dataDirectory, ignored -> {
+                    }, startupPaths);
+
+            assertEquals(DefaultPackBootstrapProvisioner.ProvisionStatus.UPDATED, updated.status());
+            assertTrue(Files.readString(levelStem).contains("\"type\": \"iris:underworld\""));
+        } finally {
+            delete(serverRoot);
+        }
+    }
+
     private static DefaultPackBootstrapProvisioner.ProvisionOptions options(
             HttpServer server,
             Path serverRoot,
@@ -610,6 +687,7 @@ public class DefaultPackBootstrapProvisionerTest {
                                 "underworld"
                         )
                 ),
+                List.of(),
                 HttpClient.newBuilder().connectTimeout(Duration.ofSeconds(2)).build(),
                 Clock.fixed(Instant.parse("2026-07-12T12:00:00Z"), ZoneOffset.UTC),
                 refreshInterval,